# Integration help

1. Dec 4, 2006

howdy, i uhh solved this problem early in the semester, and now im looking at it like wtf did i do to get the right answer....it says use the 'off the shelf formula' for first order diff eqns.

its pretty much just integrating now

y(x) = e^(x) (int[e^(-x)*-sin(2x)dx] + c)

ans => y(x)= 1/5(sin2x-2cos2x)+c

2. Dec 4, 2006

### Staff: Mentor

Are you sure you transcribed those correctly? What do you get when you differentiate the answer you've listed? Just sin and cos terms, right?

3. Dec 4, 2006

If $$y(x) = e^{x}\int e^{-x}\times -\sin 2x \; dx$$

4. Dec 4, 2006

ya thats what i dont understand..

5. Dec 4, 2006