Question

sin 4 nu /8 - cos 4 nu /8​

Answer 1

Объяснение:

$sin^4\frac{\pi }{8}-cos^4\frac{\pi }{8} =(sin^2\frac{\pi }{8} -cos^2\frac{\pi }{8})* (sin^2\frac{\pi }{8} +cos^2\frac{\pi }{8})=-(cos^2\frac{\pi }{8} -sin^2\frac{\pi }{8})*1=$

$=-cos(2*\frac{\pi }{8}) =-cos\frac{\pi }{4}=-\frac{\sqrt{2} }{2} .$

$OTBET: sin^4\frac{\pi }{4} -cos^4\frac{\pi }{4} =-\frac{\sqrt{2} }{2}.$