Question

$Prove: cos(\frac{pi}{4} - A)cos(\frac{pi}{4} - B) - sin(\frac{pi}{4} -A)sin (\frac{pi}{4}-B) = sin(A+B)$

Answer 1

Step-by-step explanation:

$cos(\frac{pi}{4} - A)cos(\frac{pi}{4} - B) - sin(\frac{pi}{4} -A)sin (\frac{pi}{4}-B) = sin(A+B)$