# Find the Indefinate Intregral

## Homework Statement

integrate cos ^3(πx-1)

## Homework Equations

1-sin^2(πx-1) = cos ^2 (πx-1)

## The Attempt at a Solution

(1-sin^2(πx-1))cos(πx-1)

Let u = πx-1
1/ πdu = dx
1-sin^2(u )cos (u)

1/ π(X-1/3sin^3(u)

Basically I'm Confused on how to get past the trig identity part.

π is Suppose to be pi i guess..

you don't really need to do a substitution for the argument of the cosine function, just use the trig identity like you did, factoring out a cos(∏x-1) and then make the subsitution u = sin(∏x -1) and du = ∏cos(∏x-1)dx and you get:

∫cos(∏x-1)dx -1/∏∫u2du

I see the answer in my book, but I'm not entirely sure there are no cosines in the answer.

Wow, that was more simple than i thought. Thank you! Its amazing how much an actual person can be when compared to a Textbook!

dextercioby