Question

√32cos^2 3π/8 - √32 sin^2 3π/8

Answer 1

$\sqrt{32}Cos^{2}\frac{3\pi }{8} -\sqrt{32}Sin^{2}\frac{3\pi }{8}=\sqrt{32}(Cos^{2}\frac{3\pi }{8}-Sin^{2}\frac{3\pi }{8}) =\sqrt{16*2}Cos(2*\frac{3\pi }{8})=\\\\=4\sqrt{2}Cos\frac{3\pi }{4}=4\sqrt{2}Cos(\pi -\frac{\pi }{4})=-4\sqrt{2}Cos\frac{\pi }{4}=-4\sqrt{2}*\frac{1}{\sqrt{2}}=\boxed{-4}$

Answer 2

Ответ:

Объяснение:

√32cos²3π/8 - √32 sin²3π/8=(√32)(cos²3π/8-sin²3π/8)=

'применим формулу cos²a-sin²a=cos2a'

=(√32)(cos2*3π/8)=(√32)(cos3π/4)==(√32)(-(√2)/2)=-(√64)/2=-8/2=-4