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.
Prove simple trigonometric identities, using the Pythagorean identity sin^2(x) + cos^2(x) = 1; the quotient identity tanx=sinx/cosx; and the reciprocal identities secx=1/cosx, cscx=1/sinx, cotx=1/tanx