- #1
LT72884
- 323
- 48
Homework Statement
Sin(2α)=-8/17
Using either double angle or half angle identities, sin,cos,tan,csc,sec and cot of alpha.
Homework Equations
The Attempt at a Solution
I tried and tried BUT i am lost because in order to find cos of alpha using identies, you still have to have cos2a or cos^2a. I have not been able to find an identy that just uses sin(2a) and spits out some sort of cos. I tried using cos2a=1-2sin^2alpha but did not end up with anything close to what the book says is the answer. Funny thing is, what ever algerbra i try on the different identities, i still get the same answer that i got previously. the book says: 4√17/17, √17/17, -4, √17/4, -√17, and -1/4 but doesn't tell me if that is cos or what function it is. haha. i don't have the solutions manual either because that was an extra 50$ i couldn't afford.
any help would be nice. pretty pics IF possible but i understand if not. thanks