Решите неравенство: sin^x<1/4

Question

Решите неравенство: sin^x<1/4<br>

Answer 1

Sin²x<1/4<br>(1-cos2x)/2<1/4<br>1-cos2x<1/2<br>cos2x>1/2
-π/3+2πn<2x<π/3+2πn<br>-π/6+πnx∈(-π/6+πn;π/6+πn)