Posted by Liddy on Friday, June 10, 2011 at 4:38pm.
1.)P(15/17,8/17) is found on the unit crcle. find sin0 and cos0.
2.)solve: x=Arc tan(sq root3).
3.)find sec0 if sin0=4/5 and 270 degrees<0<360 degrees.

Algebra II  Reiny, Friday, June 10, 2011 at 11:14pm
1. Any point P on the unit circle has coordinates (cosØ, sinØ)
so cosØ = 15/17
sinØ = 8/17
2. x = arctan(√3)
or
tanx = √3/1 , we know tan 60°=+√3
x must be in II or IV
x = 120° or 300° or 60° or ....
3. sinØ = 4/5
Ø is in IV
recognize the 3 4 5 triangle
so cosØ = 3/5