решите неравенство: 1-4sin^(2)x<0

Question

решите неравенство:

1-4sin^(2)x<0</p>

Answer 1

-4sin^(2)x<-1</span>

sin^(2)x>1/4

(1-cos2x)/2>1/4

1-cos2x>1/2

cos2x<1/2</span>

2x<+(-)arccos1/2+2</span>πn

2x<+(-)π/3+2πn</p>

x<+(-)π/6+πn</p>