Given 2pi/3 = pi/2 + pi/6. Find sin(2pi/3)
cos(pi/2 + pi/6)
= (cos pi/2)(cos pi/6) - (sin pi/2) (sin pi/6)
= (square root of 3 / 2) (square root of 3 / 2) - (2/2) (1/2)
= square root of 9/ 4 - 2/4
When I found the values (in decimal) for both the question (-0.5) and my answer (0.25), they are not equal to one another and they're suppose to be ...
What am I doing wrong?
P.S. - you need to use the special triangles to find the exact values from the radians