If sinθ=3/4 and π/2<θ<π , find cosθ .(1 point)
We know that cosθ = sqrt(1 - sin²θ) by the pythagorean identity for sine and cosine.
Since sinθ = 3/4, we have sin²θ = (3/4)² = 9/16.
Therefore, cosθ = sqrt(1 - 9/16) = sqrt(7/16) = sqrt(7)/4.
Since sinθ = 3/4, we have sin²θ = (3/4)² = 9/16.
Therefore, cosθ = sqrt(1 - 9/16) = sqrt(7/16) = sqrt(7)/4.