Pythagorean identity for sin and cos
From specialfunctionswiki
Theorem: (Pythagorean identity) The following formula holds for all $x$: $$\sin^2(x)+\cos^2(x)=1.$$
Proof: █
Theorem: (Pythagorean identity) The following formula holds for all $x$: $$\sin^2(x)+\cos^2(x)=1.$$
Proof: █