Reduction Identity

Derived from Double Angle Identity https://math.libretexts.org/Bookshelves/Algebra/Algebra_and_Trigonometry_1e_(OpenStax)/09%3A_Trigonometric_Identities_and_Equations/9.03%3A_Double-Angle_Half-Angle_and_Reduction_Formulas Formulas to reduce the power of a expression involving cos and sin

Formula

${\sin }^2(x)=\frac{1-\cos (2x)}{2}$ ${\cos }^2(x)=\frac{1+\cos (2x)}{2}$ ${\tan }^2(x)=\frac{1-\cos (2x)}{1+\cos (2x)}$