Let I =. Proceed as follows:
u = sin^{} x 
dv = e^{x} dx 
du = cos^{} x dx 
v = e^{x} 
Thus
Now use integration by parts on the remaining integral . Use the following assignments:
u = cos^{} x 
dv = e^{x} dx 
du = –sin^{} x dx 
v = e^{x} 
Thus
Note that appears on both sides of this equation. Replace it with I and then solve.
We finally obtain
