Integration of Trigonomic Functions

[Andyb43]

I have come across the problem of ∫cos^(3)x by parts. I have no idea how to integrate this. I know that I need to change the way I write cos^(3)x and I have seen people put cosx(1-sinx).

Please could you let me know where to find these equivilent ways of writing trigonomic formula? I assume there must be a table or something?

Thanks,

Andy

PS Sorry if this isn't the clearest explanation.

Homework Equations

The Attempt at a Solution

 

[SammyS]

I think you mean that cos³(x) = cos(x){1-sin²(x)} .

That's because sin²(x) + cos²(x) = 1 .

 

[Andyb43]

You're probably right. This is the problem I'm having, I don't know what the equivalent expressions are.