Mathematics · essential
Product to sum formulas for JEE
Trigonometrical identities and trigonometrical functions
Formula
\[\sin A\sin B=\dfrac{1}{2}[\cos(A-B)-\cos(A+B)],\\ \cos A\cos B=\dfrac{1}{2}[\cos(A-B)+\cos(A+B)],\\ \sin A\cos B=\dfrac{1}{2}[\sin(A+B)+\sin(A-B)],\\ \cos A\sin B=\dfrac{1}{2}[\sin(A+B)-\sin(A-B)]\]
Variables: \(A,B\) are angles.
Transformation of products, summation and equation problems.