Solve differential equation and sketch the solution curves:

                                                               

 

                                                                1.  1st order ODE, non-linear, in standard differential form

                                                                2.  Check for exact:

                                                                               

                                                                                           not exact

                                                                3.  Try condition 3) on p.96

                                                                                 (function of y)

                                                                4.  Integrating factor

                                                                               

                                                                5.  Reduce ODE to exact by multiplication by

                                                                               

                                                                     and solve as exact:

                                                                6.  Find f  :

                                                                    

                                                                                                 

                                                                                               

                                                                                               

                                                               

7.        General solution:

       

                               

 

Check for suppressed solutions:

                                                 are suppressed solutions

 

                                                                > restart;

                                                                > with(plots):

                                                                > f:={seq(exp(x)*sin(y)^2+y*cos(y)-                                                      sin(y)=c/2,c=-10..10),y=Pi,y=2*Pi,y=-Pi,y=-2*Pi}:

                                                                > implicitplot(f,x=-3..4,y=-2*Pi..2*Pi,numpoints=5000);