If sin θ = 8/17 , and θ lies in the second quadrant, find cos θ.

If sin θ = 8/17 , and θ lies in the second quadrant, find…

If sin $\theta$ = $\frac{8}{17}$ , and θ lies in the second quadrant, find cos θ.

Show answer & explanation

Correct answer: A

Explanation

The correct answer is option 1 i.e. $-\frac{15}{17}$ .

cos θ in 2nd quadrant

sin θ = 8/17

sin²θ = 64/289

cos²θ = 1 – sin²θ = 1 – 64/289 = 225/289

⇒ cos θ = ±15/17

2nd quadrant ⇒ cos θ negative ⇒ –15/17