Question

If cos θ = `3/5,` then find sin θ.

Answer 1

sin²θ + cos²θ = 1

∴ sin²θ = 1 − cos²θ

 = `1 - (3/5)^2`

= `1 - 9/25`

= `(25 - 9)/25`

∴ sin²θ = `16/25`

∴ sin θ = `4/5`