1/5 of 152 is 30.4
1/2 of 152 is 76
1/4 of 152 is 38
hope this helped :)
Left side:
1-sin²(x) = cos²(x)
1-sin²(x) / cos(x) = cos²(x) / cos(x) = <em>cos(x)</em>
Right side:
sin(2x) = 2 sin(x) cos(x)
sin(2x) / 2 sin(x) = 2 sin(x) cos(x) / 2 sin(x) = <em>cos x </em>