Given:

=

with 90 < x < 180.

Find:

=

So I actually did this:

And simplified to:

But this is not an answer choice. I feel like I have missed a step. Thank you.

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- Nov 30th 2009, 07:06 PMDaGr8GatzbyHalf Angle Formula problem
Given:

=

with 90 < x < 180.

Find:

=

So I actually did this:

And simplified to:

But this is not an answer choice. I feel like I have missed a step. Thank you. - Nov 30th 2009, 07:15 PMmr fantastic
- Nov 30th 2009, 07:23 PMDaGr8Gatzby
Edited: -1/6

- Nov 30th 2009, 07:26 PMmr fantastic
- Nov 30th 2009, 07:48 PMDaGr8Gatzby
Maybe a screenshot would help:

http://img694.imageshack.us/img694/9...91130at824.png

Still stumped on this one. - Dec 1st 2009, 02:18 AMmr fantastic