Edit: Added some tex tags
This is a question on a review I am doing, my answer doesn't match up with the answer key and I am looking for some input on what I am doing wrong.
If with in quadrant IV find:
I solved for and
Using negative angle identities and the double angle identity I end up with:
Plugging in my values gives me:
The answer key gives:
Not sure where I am messing up =\ any help is much appreciated.
I believe your answer is correct:
Given in the fourth quadrant then = -1.4 radians = -80.45 degrees.
Your answer matches:
but their answer is:
I think I may have found where whoever came up with the answer key made mistakes: if (a) they used instead of , and also (b) instead of simplifiying the term to as you have it they made it , that would explain it.
Thanks for the quick reply ebaines! That is what I was starting to think. I always assume my side is where the problem is but I am slowly learning to not always trust the given answers.