need a little help with this problem:

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- February 3rd 2007, 06:35 PMvietintegration
need a little help with this problem:

- February 3rd 2007, 07:14 PMThePerfectHacker
- February 3rd 2007, 07:17 PMAfterShock
This will help:

int(1/(1 + x^2)) = arctan(x)

Let u = cos(x)

Then,

du = -sin(x)

-du = sin(x)

Factor out the -1

-int(1/(1 + u)^2)du

-arctan(u)du

Thus, substitute in for u:

-arctan(cos(x)) + C, but you're given the limits. And thus,

-arctan(cos(Pi/2)) - [-arctan(cos(0))]

0 - (-Pi/4)

= Pi/4