2.2.5   #1a             Solve the differential equation and sketch the solution curves:

 

Solution:                1.  1st order, linear, non-homogeneous, with variable coefficients. Use variation of parameter formula.  Rewrite equation in standard normal form for linear equation:

 

                                                                

                                2.  Integrating factor:

                                                           

                                3.  General solution:

                                                   

                                                       

                                                       

                                                       

                                                       

 

                                4.  Answer:

                                                                                       

                                       

 

> restart;

> P:={seq((c/2)*exp(x)/x+exp(-x),c=-12..12)}:

> plot(P,x=-2..4,y=-4..5,color=black,axes=boxed);

 

 


                                               

 

 

 

 

 

 

 

 

 

 

 

 

 

 


                                Rewrite equation   as      

                                                                                                               

                                Then it follows that  is also a solution (suppressed solution).