Given sine, theta, equals, start fraction, 3, divided by, 4, end fractionsinθ=

4
3

and angle thetaθ is in Quadrant I, what is the exact value of cosine, thetacosθ in simplest form? Simplify all radicals if needed.
Answer
Attempt 1 out of 2

cosine, theta, equalscosθ=

cosθ = √(1 - sin²θ) = √(1 - (4/3)²) = √(1 - 16/9) = √(9/9 - 16/9) = √(-7/9) = √(7i/9) = ( √7i ) / 3