It tells me that f(x)= sin x and the question is: f(2 Theta)

I dont really know what I'm solving for, other than it says to evaluate each function, and has to do with half-angle formulas... Thanks :)

Question

It tells me that f(x)= sin x and the question is: f(2 Theta)

I dont really know what I'm solving for, other than it says to evaluate each function, and has to do with half-angle formulas... Thanks :)

anonymous · Answer

Number 29, or any of the others, they all are asking the same thing.
Pre-Calc... "yayyyy :("

anonymous · Answer

You sure? The answer is apparently -4/5
Wondering how to get there.

myininaya · Answer

|dw:1381451371156:dw|
So cos(theta)=x/sqrt(5) 
and 
    sin(theta)=y/sqrt(5)

We have to evaluate 2sin(theta)cos(theta)
Looking at your graph with the angle theta
Theta is in between 90 and 180 which means cos will be neg and sin will be pos.