Question

cos4xcos2x+sin4xsin2x>0,5

Answer 1

Cos4xcos2x+sin4xsin2x>0,5
cos(4x-2x)>0,5
cos2x>0,5
-π/3+2πk<2x<π/3+2πk
-π/6+πk<x<π/6+πk,k∈z      
Ответ x∈(-π/6+πk;π/6+πk,k∈z)

Answer 2

я не понимаю где ответ

Answer 3

не 30, а 60 градусов

Answer 4

$mathtt{cos4xcos2x+sin4xsin2x textgreater 0,5}\mathtt{cos(4x-2x) textgreater 0,5}\mathtt{cos2x textgreater 0,5}\mathtt{ -dfrac{pi}{3} textless 2x textless dfrac{pi}{3} }\mathtt{ -dfrac{pi}{3}+2pi k textless 2x textless dfrac{pi}{3}+2pi k,kinmathbb{Z}}\mathrb{xin(- dfrac{pi}{6}+pi k; dfrac{pi}{6}+pi k),kinmathbb{Z}}$