By starting with the left hand side, prove that $\frac{1-\cos^2\left(\theta\right)}{\sin\theta}=\sin\theta$1−cos2(θ)sinθ=sinθ.

Starting with the left hand side, prove the identity $\frac{1-\sin^2\left(x\right)}{\cos x}=\cos x$1−sin2(x)cosx=cosx.

Manipulate trigonometric expressions

Apply trigonometric methods in solving problems