{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 }{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 "" {MPLTEXT 1 0 14 "with(DEtools);" }}} {EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 57 "# Graphing the directionfiel d of a DE and solving the DE;" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 51 " # 1.We define a differential equation as follows" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 35 " de:=diff(y(x),x)=y/(1+x^2); " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 35 " # 2.Graphing the dir ection field" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 40 " DEp lot(de,y(x),x=-2..2,y=-2..2);" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 88 " # 3. Solving the DE. The \" _C1 \" stands for multiplicatio n by arbitrary constant C1" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 27 " f:=dsolve(de,y(x));" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 29 " # 4. Initial value problem" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 36 " f:=dsolve(\{de,y(0)=5\},y(x));" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 35 " # 5. Lets consider an other ODE: " }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 37 " de:=diff(y(x),x )=x+cos(y(x));" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 24 " d solve(de,y(x));" }}}{EXCHG {PARA 0 "> " 0 "" {MPLTEXT 1 0 90 " # No \+ answer because the ODE is too hard. We will use numerical methods (Eul er's method)" }}}}{MARK "13 0 0" 82 }{VIEWOPTS 1 1 0 1 1 1803 }