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
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.
1 answer
5 answers