{VERSION 2 3 "SUN SPARC SOLARIS" "2.3" } {USTYLETAB {CSTYLE "Maple Input" -1 0 "Courier" 0 1 255 0 0 1 0 1 0 0 1 0 0 0 0 }{CSTYLE "2D Math" -1 2 "Times" 0 1 0 0 0 0 0 0 2 0 0 0 0 0 0 }{CSTYLE "2D Comment" 2 18 "" 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 } {PSTYLE "Normal" -1 0 1 {CSTYLE "" -1 -1 "" 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 }0 0 0 -1 -1 -1 0 0 0 0 0 0 -1 0 }} {SECT 0 {EXCHG {PARA 0 "" 0 "" {TEXT -1 19 "Week 7 pp. 188-207." }} {PARA 0 "" 0 "" {TEXT -1 0 "" }}{PARA 0 "" 0 "" {TEXT -1 208 "This wee k we learn how to solve nonhomogeneous second order equations with con stant coefficients. We start with a little theory which is not restri cted to constant coefficients but just depends on linearity." }}{PARA 0 "" 0 "" {TEXT -1 37 "Exercises: p. 191- 4, 11, 18, 19, 20." }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 51 "d4:=diff(x(t),t,t)-4*diff(x( t),t)+3*x(t)=-2*exp(t);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 36 " subs(x(t)=t*exp(t),d4); simplify(\");" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 16 "dsolve(d4,x(t));" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 58 "d18:=diff(y(x),x,x)-diff(y(x),x)+y(x)=0; dsolve(d18,y (x));" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 91 "restart: d18b:=dif f(y(x),x,x)-diff(y(x),x)+y(x)=sin(x)-3*exp(2*x); s18b:=dsolve(d18b,y(x ));" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 66 "Why can't Maple do this on e like we do? Try taking the real part." }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 42 "Re(\"); # you have to assume(x,real) first!" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 12 "simplify(\");" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 46 "p. 200- 1, 17, 31, 32, 36, 41, 51, 56, 64 , 65." }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 93 "with(linalg):w:=ve ctor([exp(-x)*cos(sqrt(2)*x),exp(-x)*sin(sqrt(2)*x)]);\ndet(wronskian( w,x));" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 67 "dsolve(diff(y(x), x,x)+2*diff(y(x),x)+3*y(x)=sin(2*x),y(x),laplace);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 726 "itis:=-7/68*cos(2^(1/2)*x)*cos((2^(1/2)-2) *x)*2^(1/2)+7/68*cos(2^(1/2)*x)*cos((2+2^(1/2))*x)*2^(1/2)+1/34*cos(2^ (1/2)*x)*sin((2^(1/2)-2)*x)-1/34*cos(2^(1/2)*x)*sin((2+2^(1/2))*x)-2/1 7*sin(2^(1/2)*x)*sin((2^(1/2)-2)*x)-2/17*cos(2^(1/2)*x)*cos((2^(1/2)-2 )*x)-1/34*sin(2^(1/2)*x)*cos((2^(1/2)-2)*x)-2/17*sin(2^(1/2)*x)*sin((2 +2^(1/2))*x)-2/17*cos(2^(1/2)*x)*cos((2+2^(1/2))*x)+3/34*cos(2^(1/2)*x )*sin((2^(1/2)-2)*x)*2^(1/2)+7/68*sin(2^(1/2)*x)*sin((2+2^(1/2))*x)*2^ (1/2)-3/34*sin(2^(1/2)*x)*cos((2+2^(1/2))*x)*2^(1/2)+3/34*cos(2^(1/2)* x)*sin((2+2^(1/2))*x)*2^(1/2)-7/68*sin(2^(1/2)*x)*sin((2^(1/2)-2)*x)*2 ^(1/2)-3/34*sin(2^(1/2)*x)*cos((2^(1/2)-2)*x)*2^(1/2)+1/34*sin(2^(1/2) *x)*cos((2+2^(1/2))*x)-(-4/17*cos(2*x)-1/17*sin(2*x));" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 19 "plot(itis,x=0..Pi);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 15 "simplify(itis);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 67 "dsolve(diff(y(x),x,x)+2*diff(y(x),x)+3*y(x) =sin(2*x),y(x),laplace);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 52 "dsolve(diff(y(x),x,x)+2*diff(y(x),x)+3*y(x)=0,y(x));" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 38 "int(exp(x)*sin(sqrt(2)*x)*sin(2*x), x);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 27 "subs(\{y(0)=0,D(y)(0 )=0\},\");" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 44 "# 1 This is too ea sy. Isn't it clear that " }{XPPEDIT 18 0 "y=-3" "/%\"yG,$\"\"$!\"\"" }{TEXT -1 7 " works?" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 37 "dso lve(diff(y(x),x,x)+3*y(x)=9,y(x));" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 15 "diff(tan(x),x);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 10 "diff(\",x);" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 61 "# 17 This one is also easy because the second derivative of " } {XPPEDIT 18 0 "-11*x+1" ",&*&\"#6\"\"\"%\"xGF%!\"\"\"\"\"F%" }{TEXT -1 9 " is zero." }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 49 "restart: dsolve(diff(y(x),x,x)-y(x)=-11*x+1,y(x));" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 210 "# 31 Of course, dsolve does this one. It might be fun \+ to see how many different ways you can come up with a solution. It is linear first order variables separable the homogeneous equation succumbs to " }{XPPEDIT 18 0 "y=exp(r*x)" "/%\"yG-%$expG6#*&%\"rG\" \"\"%\"xGF)" }{TEXT -1 32 " sub. Plus Maple can do it too." }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 42 "dsolve(\{diff(y(x),x)-y(x)=1 ,y(0)=0\},y(x));" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 18 "# 32 Using M aple:" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 52 "dsolve(\{diff(h(x) ,x,x)=6*x,h(0)=3,D(h)(0)=-1\},h(x));" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 71 "#36 If you would rather not type theta you can use t (or x, \+ or ...)." }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 100 "dsolve(\{diff( y(theta),theta,theta)-y(theta)=exp(theta)-exp(-theta)+2, y(0)=0, D(y)( 0)=0\}, y(theta));" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 4 "# 56" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 81 "dsolve(diff(y(x),x,x,x)*2+3* diff(y(x),x,x)+diff(y(x),x)-4*y(x) = exp(-x), y(x));" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 28 "subs(\{_C1=0,_C2=0,_C3=0\},\");" }} }{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 25 "solve(2*r^3+3*r^2+r-4,r);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 9 "evalf(\");" }}}{EXCHG {PARA 0 "" 0 "" {TEXT -1 35 "p. 206- 11, 21, 22, 23, 24, 27, 28." }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 0 "" }}}}{MARK "37 0 0" 0 } {VIEWOPTS 1 1 0 2 1 1805 }