Please help :))

Question

if cos(o) = - sqrt (3) / 2 and o is in the 3rd quadrant, find sin (o)

Answer 1

Looking at the unit circle, if cos(θ) = -√3/2 then sin(θ) = -1/2.

Or if cos(θ) = -x/h then y² = h²-x² = 4-3 = 1 --> y=±√1 = ±1 Take the negative value since 3rd quadrant

sin(θ) = y/h = -1/2