Question

Given that sin θ = 0.5, where π/2 < θ < π , find cos θ .

Answer 1

cos theta is -0.866

Explanation:

We have the range as between 90 and 180 degrees (pi is the same as 180 degrees)

The quadrant we are considering here is the 2nd quadrant

Mathematically;

if sin theta = 0.5

theta = arc•sin 0.5

theta = 30 degrees

The angle on the second quadrant is of the likes;

180-theta

so we have 180-30

and that is 150 degrees

cos (150) is thus; -0.866