R rooney New member Joined Feb 9, 2008 Messages 25 Feb 11, 2008 #1 integral((e^x)(sinx)dx) I tried to integrate by parts, and ended up with (sinx)(e^x)-integral((cosx)(e^x) which I don't know what to do with.
integral((e^x)(sinx)dx) I tried to integrate by parts, and ended up with (sinx)(e^x)-integral((cosx)(e^x) which I don't know what to do with.
N n00blar New member Joined Feb 10, 2008 Messages 3 Feb 11, 2008 #2 Re: integral by parts What you want to do here is use integration by parts again: \(\displaystyle \int {e^x}{sin(x)} dx = {e^x}{sin(x)} - \int {e^x}{cos(x)} dx\) \(\displaystyle \int {e^x}{cos(x)} dx = {e^x}{cos(x)} + \int {e^x}{sin(x)} dx\) \(\displaystyle \int {e^x}{sin(x)} dx = {e^x}{sin(x)} - {e^x}{cos(x)} - \int {e^x}{sin(x)} dx\) The rest is just simple math. =)
Re: integral by parts What you want to do here is use integration by parts again: \(\displaystyle \int {e^x}{sin(x)} dx = {e^x}{sin(x)} - \int {e^x}{cos(x)} dx\) \(\displaystyle \int {e^x}{cos(x)} dx = {e^x}{cos(x)} + \int {e^x}{sin(x)} dx\) \(\displaystyle \int {e^x}{sin(x)} dx = {e^x}{sin(x)} - {e^x}{cos(x)} - \int {e^x}{sin(x)} dx\) The rest is just simple math. =)
