verify the identity: (1 -sinx) / cosx = cosx / (1 +sinx)
\(\dfrac{1-\sin x}{\cos x}=\dfrac{\cos x}{1+\sin x}\\ \cos^2 x=(1-\sin x)(1+\sin x)\\ \cos^2 x=1-\sin^2 x\\ \sin^2 x+\cos ^2 x=1\)It IS the identity.
