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Homework Help: Integration of Trigonomic Functions

  1. Oct 4, 2011 #1
    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?



    PS Sorry if this isn't the clearest explanation.

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Oct 4, 2011 #2


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

    That's because sin2(x) + cos2(x) = 1 .
  4. Oct 4, 2011 #3
    You're probably right. This is the problem I'm having, I don't know what the equivalent expressions are.
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