Originally Posted by xfyz

Solve by using Undetermined Coefficients:

y''+y=e^x+x^3 , y(0) = 2 , y'(0) = 0

so I found r to equal + i which gives the first particular solution
y(x) = C1*cosx+C2sinx

for the first side I got yp(x) = Ae^x and both y' and y'' to equal Ae^x.

I solved for A to get 1/2.

can someone show me the 2nd part with the x^3? what would my yp(x) be? thanks