-VD:CMR
a ) Sin μ + Cos μ = \(\sqrt{2}Sin\left(\mu+\dfrac{\pi}{4}\right)\)= \(\sqrt{2}Cos\left(\mu-\dfrac{\pi}{4}\right)\)
b) 4\(Sin\left(\alpha+\dfrac{\pi}{3}\right)\) . Sin\(\left(\alpha-\dfrac{\pi}{3}\right)\) = 4Sin2 \(\alpha\) \(-\) 3
c) Cos(a+b) . Cos(a-b) = Cos2a - Sin2 a