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I'm busy studying for my Calculus exam and came across something that I'm not too sure about. The question asks to use z-substitution to determine an integral. The actual question is:

Use z=tan(x/2) to determine the integral:
Integral from 0 to pi/3 of dx/(3+2cosx)

Is Z-Substitution the same as normal substitution but they give you what to use? Or is there another method?

Any help would be appreciated. Thanks in advance!

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up vote 2 down vote accepted

This is a standard substitution for evaluating integrals of rational functions of trigonometric functions. A more common name is the Weierstrass substitution.

You will find full details in the Wikipedia article linked to above.

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Thank you! Really helpful – nickcorin Nov 6 '12 at 9:09

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