Question

3costheta-sin(theta/2)-1=0

Answer 1

use the identity cos theta = 1 - 2 sin^2(theta/2)

Answer 2

let t = sin(theta/2) so

3(1 - t^2) - t - 1 = 0
3 - 3t^2 - t -1 = 0
3t^2 + t - 2 = 0

solve this for t
then equate the solutions to sin(theta/2)

Answer 3

youre a rock star thanks :)