Two of the questions in the review aren't really something that was directly covered in the class, and I am having trouble understanding it and also trouble researching it myself.
The problem says:
prove the identity
sin(2x) = 2 (cos x) [cos (pi/2-x)]
then use a right triangle to show angles x and (pi/2 - x)
I don't really understand what my professor is asking me to do. I mean, I know
sin(2x) = 2 cos(x)(sin x)
so then i guess sin(x) = cos(pi/2-x) ? But I mean I don't really know how to prove that, or what my professor wants me to *show* on the right triangle. I could show any given 2 angles that add to 90 on the right triangle and label them x and (pi/2-x) but wtf would the point of that be?
P.S. I'll delete this blog after some time or after I get help because I know how strict TL can be about shitty blogs