integral 0 to infinite (x^ 3)(e^-8x) cos(5x) dx
should I do integrate by part?
help me
To type equations like I did, you use LaTeX to do it. LaTeX Tutorial.
Yes, you would use integration by parts. For the $\displaystyle \cos (5x)$ part you would also need to use integration by u-substitution as well as integration by parts.
$\displaystyle \displaystyle \int f'(x)g(x)h(x)dx = f(x)g(x)h(x) - \int f(x)g'(x)h(x)dx - \int f(x)g(x)h'(x)dx$