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<Text-field prompt="&gt; " style="Maple Input" layout="Normal">restart:</Text-field>
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<Group labelreference="L3" drawlabel="true">
<Input>
<Text-field style="Text" layout="Normal">Tangent Planes to Level Surfaces</Text-field>
<Text-field style="Text" layout="Normal">Maplet by Cangelose and Davidson</Text-field>
</Input>
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<Group labelreference="L3" drawlabel="true">
<Input>
<Text-field style="Text" layout="Normal"></Text-field>
</Input>
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<Group labelreference="L6" drawlabel="true">
<Input>
<Text-field style="Text" layout="Normal">Corrections by Yasskin:</Text-field>
<Text-field style="Text" layout="Normal">surface must be an equation</Text-field>
<Text-field style="Text" layout="Normal">modified text and captions</Text-field>
<Text-field style="Text" layout="Normal">improved colors</Text-field>
<Text-field style="Text" layout="Normal">thepoint was pointless</Text-field>
<Text-field style="Text" layout="Normal">Fixed the hint.</Text-field>
<Text-field style="Text" layout="Normal">It is not the partial derivative of x. It is the partial derivative of f with respect to x.</Text-field>
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<Group labelreference="L3" drawlabel="true">
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">with(Maplets[Elements]):with(Maplets[Tools]): with(plots): with(student): with(linalg): with(plottools):
StartEngine();</Text-field>
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<Group labelreference="L28" drawlabel="true">
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">lightorange := &quot;#FFB300&quot;:</Text-field>
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<Group labelreference="L27" drawlabel="true">
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">randomize():</Text-field>
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<Group labelreference="L26" drawlabel="true">
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">great := [</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Great job! &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Right on the mark. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Great. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; That's absolutely right. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Awesome. You're unstoppable. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Correct. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; WOW, nailed that one. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; You got it! &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; YES! Right on. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Way to go. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Don't stop now. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; I knew you could do it! &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Perfect. You're unstoppable. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Radical Dude. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Power house. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Sweet! Keep on Rockin'. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; You rock! &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; You got those mad skills. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Awesome! &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Wowzers! That was great! &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Awesome man! &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Good job! You really know what you are doing. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; You're awesome kid. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Tearing it up. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Right on the money. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; High Five!!!!! &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; What a nerd! &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; You're so money. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; You're a genious. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; You hit the nail on the head. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Excellent! &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; If I had a cookie, I'd give it to you. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; You're a winner. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; That's a winner. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Whoop! Way to go. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; That's the way, ah ha ah ha, I like it. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Oh yeah! &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; You're the bomb! &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; That was fantastic! &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Oh Snap! &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; That's krunk! &quot;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">]:</Text-field>
</Group>
<Group labelreference="L25" drawlabel="true">
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">randgreat := rand(1..nops(great)):</Text-field>
</Group>
<Group labelreference="L24" drawlabel="true">
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">nextquest := [</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot;Keep it up.&quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot;Keep going.&quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot;On to the next function.&quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot;Try another function.&quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot;Find another tangent line.&quot;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">]:</Text-field>
</Group>
<Group labelreference="L23" drawlabel="true">
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">randnext := rand(1..nops(nextquest)):</Text-field>
</Group>
<Group labelreference="L22" drawlabel="true">
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">sorry := [</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Sorry, that's not right. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Nope, but don't give up. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Not quite, it's a little off. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Bummer, thought you would get it this time. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Close, but no cigar. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Slightly off. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; If you need help, please ask a human. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; I don't know where you went wrong. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Sorry, killer problem. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; No, but don't blow it off. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; D'oh! &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; That's whack. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Yikes! Really close. You'll get it next time. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Puma! Thought you would get it this time. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Nice try, but your answer is wrong. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Ask your neighbor for help, just not if this is a quiz, THAT would be cheating. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Brutal kid. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; That won't fly, try to be more like Superman. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; So close and yet so far. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; So, that was just practice. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Ooooh...close. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; A swing and a miss. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Better luck next time. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Oops. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Tilt. Play again. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; I know you can do better. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Sorry, you're not as great as Lisa the Great &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Better luck next time. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Tisk, tisk. It's a tough one. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; It takes a lot of wrongs to make a right. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Even Einstein didn't get everything right. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Oh man, you were so close. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Today's not your lucky day. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Don't quit your day job. &quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; You're colder than a polar bear's toenail. &quot;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">]:</Text-field>
</Group>
<Group labelreference="L21" drawlabel="true">
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">randsorry := rand(1..nops(sorry)):</Text-field>
</Group>
<Group labelreference="L20" drawlabel="true">
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">tryagain := [</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot;Try the hint.&quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot;Fix your answer and check it again.&quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot;Give it another try.&quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot;Try again.&quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot;Please try again.&quot;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">]:</Text-field>
</Group>
<Group labelreference="L19" drawlabel="true">
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">randtry := rand(1..nops(tryagain)):</Text-field>
</Group>
<Group labelreference="L18" drawlabel="true">
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">showit := [</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; OK That's just practice. But try doing it yourself.&quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; That's fine for practice. Try doing it yourself.&quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; Read the hint and enter an answer yourself.&quot;,</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">&quot; So that was practice. Try doing it yourself.&quot;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">]:</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">randshow := rand(1..nops(showit)):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal"> </Text-field>
</Group>
<Group labelreference="L17" drawlabel="true">
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">### here are the functions and the values for the functions###</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">i:=0:</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">i:=i+1;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">funcs[i]:=x^2+4*y^2-z;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">A[i]:=[[-3,2,1],[5,2,9],[2,5,6],[8,4,7],[8,0,6]]:
mini[i]:=[[-6, -1,-2], [2,-1,6], [-1,2,3], [5,1,4],[5,-3,3]]:
maxi[i]:=[[0,5,4], [8,5,12], [5,8,9],[11,7,10],[11,3,9]]:</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">randpt[i]:=rand(1..nops(A[i])):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">i:=i+1;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">funcs[i]:=x^2-y^2+z^3;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">A[i]:=[[9,5,6],[4,4,3],[9,3,3],[5,7,1],[1,1,2]]:
mini[i]:=[[6,2,3],[1,1,0],[6,0,0],[2,4,-2],[-2,-2,-1]]:
maxi[i]:=[[12,8,9],[7,7,6],[12,6,6],[8,10,4],[4,4,5]]:</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">randpt[i]:=rand(1..nops(A[i])):
i:=i+1;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">funcs[i]:=exp(x)+exp(y)*exp(z);</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">A[i]:=[[-3,1,1],[ln(5), ln(2), ln(1)]]:
mini[i]:=[[.001,.001,.001],[.001,.001,.001]]:
maxi[i]:=[[4,4,4], [4,3,3]]:</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">randpt[i]:=rand(1..nops(A[i])):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">i:=i+1;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">funcs[i]:=x^2+y^2+z^2;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">A[i]:=[[0, 6, 4], [3, 2, 6], [4, 3, 2], [6, 4, 3], [2,0,1]]:
mini[i]:=[[-3,3,1],[0,-1,3],[1,0,-1],[3,1,0],[-1,-3,-2]]:
maxi[i]:=[[3,9,7],[6,5,9],[7,6,5],[9,7,6],[5,3,4]]:</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">randpt[i]:=rand(1..nops(A[i])):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">i:=i+1;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">funcs[i]:=sin(x*y)+z;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">A[i]:=[[0, Pi/6, 1], [3, Pi/2, 0],[Pi,1,1]]:
mini[i]:=[[-.5,0,0],[2.5,1,-.5],[.5,.5,2.5]]:
maxi[i]:=[[.5,.5,2],[3.5,1.8,.5],[1.5,1.5,3.5]]:</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">randpt[i]:=rand(1..nops(A[i])):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">i:=i+1;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">funcs[i]:=x^2*y^3-cos(z);</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">A[i]:=[[-3, -2, 3*Pi/2], [5,4,Pi/2], [1, 2, 2*Pi]]:
mini[i]:=[[-6,-5,0],[2,1,-2],[-2,-1,3]]:
maxi[i]:=[[0,1,3*Pi],[8,7,3*Pi/2],[4,5,6*Pi]]:</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">randpt[i]:=rand(1..nops(A[i])):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">i:=i+1;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">funcs[i]:=x^4+y*z;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">A[i]:=[[1, 2, 4], [3, 4, 5], [3,9,2]]:
mini[i]:=[[-2,-1,1],[4,-2,2],[0,3,5]]:
maxi[i]:=[[4,5,7],[10,4,8],[6,9,11]]:</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">randpt[i]:=rand(1..nops(A[i])):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">randfunc := rand(1..i):
i:='i':

</Text-field>
</Group>
<Group labelreference="L18" drawlabel="true">
<Input>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal"></Text-field>
</Input>
</Group>
<Group labelreference="L16" drawlabel="true">
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">Show_Function := proc()
  local pointi, minif, maxif, mysubs, fabc, Nx, Ny, Nz, fgraph, tgraph;
  global randfunc, whichfunc, funcs, func, A, randpt, whichpoint, x, a, dfx, dfy, dfz, functan;
  options `Copyright 2006, Philip B. Yasskin, Texas A&amp;M Univ.`;
  whichfunc := randfunc();
  func := funcs[whichfunc]; 
   ##assigning the function we're working with##
  pointi:=randpt[whichfunc](); ##picking a random point##
  a := A[whichfunc][pointi];
  minif:=mini[whichfunc][pointi];
  maxif:=maxi[whichfunc][pointi];
  mysubs:=equate([x,y,z],a);
  fabc:=subs(mysubs,func);
  dfx := diff(func,x); 
   ##partial of f wrt x##
  Nx:=subs(mysubs, dfx): 
   ##partial of f wrt x at a##
  dfy := diff(func,y); 
   ##partial of f wrt y##
  Ny:=subs(mysubs, dfy):
   ##partial of f wrt y at a##
  dfz := diff(func,z);
   ##partial of f wrt z##
  Nz:=subs(mysubs, dfz):
   ##partial of f wrt z at a##
  functan:= Nx*(x-a[1])+Ny*(y-a[2])+Nz*(z-a[3]):
   ##tangent plane##
  fgraph:=implicitplot3d(func=fabc,x=minif[1]..maxif[1], y=minif[2]..maxif[2], z=minif[3]..maxif[3], color=red):
   ##graph of f##
  tgraph:=implicitplot3d(functan=0, x=minif[1]..maxif[1], y=minif[2]..maxif[2], z=minif[3]..maxif[3], color=green): 
   ##graph of tangent plane##
  Set('myplot' = display(fgraph,tgraph, axes=normal)):
  Set('fMML' = (func=fabc)): </Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  Set('pointMML' = a):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  Set('fx' = &quot;&quot;):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  Set('fy' = &quot;&quot;):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  Set('fz' = &quot;&quot;):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  Set('ftan' = &quot;&quot;):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  Set('fxck' = &quot;&quot;, 'fxck'(background)=white, 'fxck'(foreground) = black):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  Set('fyck' = &quot;&quot;, 'fyck'(background)=white, 'fyck'(foreground) = black):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  Set('fzck' = &quot;&quot;, 'fzck'(background)=white, 'fzck'(foreground) = black):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  Set('ftanck' = &quot;&quot;, 'ftanck'(background)=white, 'ftanck'(foreground) = black):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  Set('reply' = &quot;&quot;, 'reply'(background)=white, 'reply'(foreground) = black):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  if whichfunc = 3</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">    then Set('reply' = &quot;Enter the exponential function as exp(x).&quot;, 'reply'(background)=lightorange, 'reply'(foreground) = black)</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  end if;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">end proc:</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal"> </Text-field>
</Group>
<Group labelreference="L15" drawlabel="true">
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">Check_fx := proc()</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  local user_fx;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  global dfx, x;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  options `Copyright 2006, Philip B. Yasskin, Texas A&amp;M Univ.`;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  user_fx := Get('fx'::algebraic, corrections=true, update=true):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  Set('reply' = &quot;&quot;, 'reply'(background)=white, 'reply'(foreground) = black);</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  if simplify(normal(dfx - user_fx))&lt;&gt; 0 then</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">    Set('fxck' = &quot;incorrect&quot;, 'fxck'(background)=red, 'fxck'(foreground) = white):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  else</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">    Set('fxck' = &quot; correct &quot;, 'fxck'(background)=green, 'fxck'(foreground) = black):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  end if;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">end proc:</Text-field>
</Group>
<Group labelreference="L14" drawlabel="true">
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">Show_fx := proc()</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  global dfx, x;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  options `Copyright 2006, Philip B. Yasskin, Texas A&amp;M Univ.`;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  Set('fx' = dfx):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  Set('fxck' = &quot; shown &quot;, 'fxck'(background)=lightorange, 'fxck'(foreground) = black):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  Set('reply' = showit[randshow()], 'reply'(background)=lightorange, 'reply'(foreground) = black):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">end proc:</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal"> </Text-field>
</Group>
<Group labelreference="L13" drawlabel="true">
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">Check_fy := proc()</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  local user_fy;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  global dfy, x;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  options `Copyright 2006, Philip B. Yasskin, Texas A&amp;M Univ.`;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  user_fy := Get('fy'::algebraic, corrections=true, update=true):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  Set('reply' = &quot;&quot;, 'reply'(background)=white, 'reply'(foreground) = black);</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  if simplify(normal(dfy - user_fy))&lt;&gt; 0 then</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">    Set('fyck' = &quot;incorrect&quot;, 'fyck'(background)=red, 'fyck'(foreground) = white):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  else</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">    Set('fyck' = &quot; correct &quot;, 'fyck'(background)=green, 'fyck'(foreground) = black):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  end if;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">end proc:</Text-field>
</Group>
<Group labelreference="L12" drawlabel="true">
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">Show_fy := proc()</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  global dfy, x;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  options `Copyright 2006, Philip B. Yasskin, Texas A&amp;M Univ.`;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  Set('fy' = dfy):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  Set('fyck' = &quot; shown &quot;, 'fyck'(background)=lightorange, 'fyck'(foreground) = black):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  Set('reply' = showit[randshow()], 'reply'(background)=lightorange, 'reply'(foreground) = black):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">end proc:</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal"> </Text-field>
</Group>
<Group labelreference="L11" drawlabel="true">
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">Check_fz := proc()</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  local user_fz;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  global dfz, x;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  options `Copyright 2006, Philip B. Yasskin, Texas A&amp;M Univ.`;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  user_fz := Get('fz'::algebraic, corrections=true, update=true):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  Set('reply' = &quot;&quot;, 'reply'(background)=white, 'reply'(foreground) = black);</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  if simplify(normal(dfz - user_fz))&lt;&gt; 0 then</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">    Set('fzck' = &quot;incorrect&quot;, 'fzck'(background)=red, 'fzck'(foreground) = white):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  else</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">    Set('fzck' = &quot; correct &quot;, 'fzck'(background)=green, 'fzck'(foreground) = black):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  end if;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">end proc:</Text-field>
</Group>
<Group labelreference="L10" drawlabel="true">
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">Show_fz := proc()</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  global dfz, x;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  options `Copyright 2006, Philip B. Yasskin, Texas A&amp;M Univ.`;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  Set('fz' = dfz):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  Set('fzck' = &quot; shown &quot;, 'fzck'(background)=lightorange, 'fzck'(foreground) = black):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  Set('reply' = showit[randshow()], 'reply'(background)=lightorange, 'reply'(foreground) = black):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">end proc:</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal"> </Text-field>
</Group>
<Group labelreference="L9" drawlabel="true">
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">Check_ftan := proc()</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  local user_ftan;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  global functan, x;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  options `Copyright 2006, Philip B. Yasskin, Texas A&amp;M Univ.`;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  user_ftan := Get('ftan'::algebraic, corrections=true, update=true):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  if simplify(normal(functan - user_ftan))&lt;&gt; 0 then</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">    Set('ftanck' = &quot;incorrect&quot;, 'ftanck'(background)=red, 'ftanck'(foreground) = white):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">    Set('reply' = cat(sorry[randsorry()], tryagain[randtry()]), 'reply'(background)=red, 'reply'(foreground) = white):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  else</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">    Set('ftanck' = &quot; correct &quot;, 'ftanck'(background)=green, 'ftanck'(foreground) = black):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">    Set('reply' = cat(great[randgreat()], nextquest[randnext()]), 'reply'(background)=green, 'reply'(foreground) = black):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  end if;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">end proc:</Text-field>
</Group>
<Group labelreference="L8" drawlabel="true">
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">Show_ftan := proc()</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  global dfz, x;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  options `Copyright 2006, Philip B. Yasskin, Texas A&amp;M Univ.`;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  Set('ftan' = functan):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  Set('ftanck' = &quot; shown &quot;, 'ftanck'(background)=lightorange, 'ftanck'(foreground) = black):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  Set('reply' = showit[randshow()], 'reply'(background)=lightorange, 'reply'(foreground) = black):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">end proc:</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal"> </Text-field>
</Group>
<Group labelreference="L7" drawlabel="true">
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">Hint := proc()</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">global a;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">options `Copyright 2006, Philip B. Yasskin, Texas A&amp;M Univ.`;</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">Set('reply' = cat(&quot;The tangent plane is   Nx (x-a) + Ny (y-b) + Nz (z-c) = 0.\nNote: Nx = df/dx(a,b,c) which is the partial derivative of f with respect to x evaluated at (a,b,c).&quot;), 'reply'(background)=lightorange, 'reply'(foreground) = black):</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">end proc:</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal"> </Text-field>
</Group>
<Group labelreference="L6" drawlabel="true">
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">Tangent_Line := Maplet(onstartup = RunWindow(MAIN), Font[helv10](&quot;helvetica&quot;,10),</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">Window[MAIN]( 'title'=&quot;Tangent Planes to Level Surfaces&quot;, 'defaultbutton'='BHint', 
[ halign=none, background=wheat,
  [ halign=none, background=wheat,
    Button['Bnew'](&quot;New Equation&quot;, Evaluate('function' = &quot;Show_Function&quot;), background=turquoise),
    HorizontalGlue(),
    Button['BHint'](&quot;Hint&quot;, Evaluate('function' = &quot;Hint&quot;), background=lightorange),
    Button(&quot;Quit&quot;, Shutdown(), background=pink)
  ],
  BoxRow( background=wheat,
    BoxColumn( border=true, background=wheat,
      caption=&quot;Rotate the plot with the mouse.&quot;,
      Plotter['myplot'](height=250, width=250)
    ),
    BoxColumn( halign=none, inset=0, background=wheat,
      BoxRow( halign=none, border=true, background=wheat,
        caption = &quot;Goal:  Find the tangent plane to&quot;,
        &quot;f(x,y,z) =&quot;,
        MathMLViewer[fMML]('value'=MathML[Export](&quot; &quot;), 'width'=200, 'height'=60),
        &quot;at (x,y,z) =&quot;,
        MathMLViewer[pointMML]('value'=MathML[Export](&quot; &quot;), 'width'=100, 'height'=60)
      ),
      BoxColumn( halign=none, border=true, inset=0, background=wheat,
        caption = &quot;Enter the partial derivatives of f:&quot;,
        [ halign=none, background=wheat,
          &quot;df/dx = &quot;,
          TextField['fx']('width'=20, 'background'=turquoise),
          HorizontalGlue(),
          Button['Bfxck'](&quot;Check&quot;, Evaluate('function' = &quot;Check_fx&quot;), background=green),
          TextField['fxck']('width'=6, editable=false, background=white),
          Button['Bfxsh'](&quot;Show&quot;, Evaluate('function' = &quot;Show_fx&quot;), background=lightorange)
        ],
        [ halign=none, background=wheat,
          &quot;df/dy = &quot;,
          TextField['fy']('width'=20, 'background'=turquoise),
          HorizontalGlue(),
          Button['Bfyck'](&quot;Check&quot;, Evaluate('function' = &quot;Check_fy&quot;), background=green),
          TextField['fyck']('width'=6, editable=false, background=white),
          Button['Bfysh'](&quot;Show&quot;, Evaluate('function' = &quot;Show_fy&quot;), background=lightorange)
        ],
        [ halign=none, background=wheat,
          &quot;df/dz = &quot;,
          TextField['fz']('width'=20, 'background'=turquoise),
          HorizontalGlue(),
          Button['Bfzck'](&quot;Check&quot;, Evaluate('function' = &quot;Check_fz&quot;), background=green),
          TextField['fzck']('width'=6, editable=false, background=white),
          Button['Bfzsh'](&quot;Show&quot;, Evaluate('function' = &quot;Show_fz&quot;), background=lightorange)
        ]
      ),
      BoxRow( halign=none, border=true, background=wheat,
        caption = &quot;Enter the tangent plane:&quot;,
        TextField['ftan']('width'=26, 'background'=turquoise),
        &quot;= 0&quot;,
        HorizontalGlue(),
        Button['Bftanck'](&quot;Check&quot;, Evaluate('function' = &quot;Check_ftan&quot;), background=green),
        TextField['ftanck']('width'=6, editable=false, background=white),
        Button['Bftansh'](&quot;Show&quot;, Evaluate('function' = &quot;Show_ftan&quot;), background=lightorange)
      )
    )
  ),</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">  TextBox['reply']('width'=70, 'height'=2, 'editable'='false', background=white ),
      [ halign=none, background=&quot;#DDFFFF&quot;, inset=0, spacing=0,
        &quot;Programmers: Carolyn Davidson and Lisa Cangelose&quot;, 
        HorizontalGlue(),
        <Font encoding="UTF-8">&quot;\302\251 Copyright: </Font>P. Yasskin 2006&quot;
      ]</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">])</Text-field>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">):</Text-field>
</Group>
<Group labelreference="L4" drawlabel="true">
<Text-field prompt="&gt; " style="Maple Input" layout="Normal">Maplets[Display]( Tangent_Line );</Text-field>
</Group>
<Group labelreference="L3" drawlabel="true">
<Input>
<Text-field prompt="&gt; " style="Maple Input" layout="Normal"></Text-field>
</Input>
</Group>
</Worksheet>
