Question

Докажите тождество sin(π/4+α)=cos(π/4-α)

Answer 1

$sin beta =cos(frac{pi}{2}- beta ); ; to ; ; beta =frac{pi}{4}+ alpha \\sin(frac{pi}{4}+ alpha )=cos(frac{pi}{2}-(frac{pi}{4}+ alpha ))=cos(frac{pi}{4}- alpha )$