Question

Given tantheta = 4/3 and pi < theta < 3pi/2; find cos2theta

Answer 1

D

Explanation:

edge

Answer 2

d. -7/25

Explanation:

π<θ<3π/2 in third quadrant

tanθ = 4/3

sinθ = - 4/5

cosθ = - 3/5

cos 2θ = cos²θ - sin²θ = (- 3/5)² - (- 4/5)² = 9/25 - 16/25 = - 7/25