Evaluate the indefinite integral of:
[x^4 * sin(x)]dx

I would like a hint please. I tried substitution like:
u = x^4, then du = 4x^3 dx
u = x^3, then du = 3x^2 dx

However, I don't know how to get a relationship between sin(x) and that (x) term.

Question

Evaluate the indefinite integral of:
[x^4 * sin(x)]dx

I would like a hint please. I tried substitution like:
u = x^4, then du = 4x^3 dx
u = x^3, then du = 3x^2 dx

However, I don't know how to get a relationship between sin(x) and that (x) term.

anonymous · Answer

parts for this one

anonymous · Answer

and it is a real pain, because each time you integrate by parts you are going to reduce the power on x by 1, so you will have to do it four times!

anonymous · Answer

Wow I knew that was the only alternative. There is no substitution rule that will work for this

anonymous · Answer

?

anonymous · Answer

nope

anonymous · Answer

gotta grind it til you find it.
i would cheat

anonymous · Answer

use Integration by parts.. let u = x^4 and dv = sinx... then use uv - [v du

anonymous · Answer

because really, you are going to have to integrate by parts 4 times.  have fun

anonymous · Answer

http://www.wolframalpha.com/input/?i=x^4sin%28x%29

anonymous · Answer

NOOO! Don't show me the answer. All I wanted to know was that I have to use integration by parts.

anonymous · Answer

OK thank you very much.

anonymous · Answer

then don't look, just keep integrating