θ is in QIV, so x>0 and y<0
cosθ = x/r = 8/17
so,
x = 8
y = -15
r = 17
Now recall the other trig functions:
sinθ = y/r
tanθ = y/x
Cosine theta=8/17 and 270 degrees is < theta, and theta is< 360
2 answers
Sin= -15/17
Cos= 8/17
Tan= -15/8
Csc=-17/15
Sec= 17/8
Cot= -8/15
Cos= 8/17
Tan= -15/8
Csc=-17/15
Sec= 17/8
Cot= -8/15