Problem:


Attempt:

u =
du =
v =
dv =

Focusing on

u =
du =
v =
dv =

Focusing on



Put everything back together







Answer:


Correct Answer:


Where did I go wrong?

Integrating sinx becomes -cosx, not cosx.

I tried this problem, and I made a mistake somewhere because I got

Originally Posted by chengbin

Integrating sinx becomes -cosx, not cosx.

I tried this problem, and I made a mistake somewhere because I got

Thanks, that was my problem(even though it was a derivative that didn't change into a negative)

Hello,

Another method :






And


Hence


What's good with this is that there is no need to integrate cos or sin, and mess up with the signs


In the first quote :

u = cos(x)
du = sin(x) dx

This is false, it's du=-sin(x) dx

How do you box your answer?

\boxed{ CONTENT }

You can always quote a post to take a look at its contents (or click the latex image).