Question

Solve . cos(2x) > -1/2 . Find x values which are in the area [0;Pi]

Answer 1

u=2x

cos(u)=-1/2


so u from 0 to 120 works

0 < u<120
0 < 2x<120
0 <x<60

Answer 2

in area [0;Pi] values of 2x= [0;Pi] hance value of x={0,pi/2}

Answer 3

"x={0,pi/2}"
Cos(2 Pi/2)= cos (Pi)= -1 <-1/2