Question

Find sin theta if cos theta is 4/5

Answer 1

Explanation:

hello :

cos²θ +sin²θ = 1 and cosθ =4/5

(4/5)² + sin²θ = 1 so : sin²θ = 1 - 16/25

sin²θ = 9/25 = (3/5)²

sinθ = 3/5 or sinθ = - 3/5 because : (3/5)²= (- 3/5)²= 9/25