The equation is...

I substituted in place of and in place of .

I now have...

I tried cross multiplying to get the left side as one fraction, but it doesn't seem to get me anywhere. It seems like there is some concept i am missing because i end up getting stuck in the same place with a lot of different problems like this.

note: i am 25 years old and not in high school or college. I am learning trig. because I want to.

Thanks!