# Math Help - integrate

1. ## integrate

could you plz help!

can you find in terms of n the 3 possible values of ∫ cos nx dx with limits π and π/2 ?

Thanks

2. The integral should be easy enough. Just treat n as a constant and let u = nx. You should get:

$\int_{\frac{\pi}{2}}^{\pi} \cos (nx) \: dx = ... = \frac{1}{n} \left[\sin(n\pi) - \sin \left(\frac{n\pi}{2}\right) \right]$

Are you suppose to find any 3 values that your definite integral can have depending on the value of n? Pick n = an even number, n = an odd number, n = a fraction such as 1/2.

3. ## Re:integrate

the exact quetion is:

if n is a positive integer, find in terms of n the 3 possible values of

Thanks

4. Simply consider n = 1, 2, and 3