Question

if sin theta = a/b then cos theta=​

Answer 1

sin θ =a/b

We know, sin² θ + cos² θ = 1

sin² A = 1 - cos² A

sin A = √(1-cos² A

So, cos θ = √(1 - a²/b²) = √((b² - a²)/b²) = √(b² - a²)/b

Hence, cos θ = √(b² – a²)/b