Question

Решите неравенство: sin^x<1/4

Answer 1

sin²x<1/4
(1-cos2x)/2<1/4
1-cos2x<1/2
cos2x>1/2
-π/3+2πn<2x<π/3+2πn
-π/6+πn<x<π/6+πn
x∈(-π/6+πn;π/6+πn)