Question

The angle θ lies in Quadrant I. cosθ=35 What is tanθ?

Answer 1

Explanation:

sin2θ + cos2θ = 1

sin2θ + (3/5)2 = 1

sin2θ = 1 - (3/5)2

sin2θ = 1 - 9/25

sin2θ = 16/25

sin θ = ±√[ 16/25 ]

sin θ = ± 4 / 5

Since θ is in Quadrant I, sin θ is positive.

sin θ = 4 / 5

tan θ = sin θ / cos θ

tan θ = ( 4/5 ) / (3/5 )

tan θ = 4 / 3