Find all the solutions of the equation in the interval [0,2π] sin 2a - cos a = 0

Answer 1

Hi Roberto,

sin 2a - cos a = 0

2(sin a)(cos a) - cos a = 0 (using double-angle formula)

cos a (2 sin a - 1) = 0

cos a = 0 or 2 sin a - 1 = 0

cos a = 0 or sin a = 1/2

Can you try to solve it with the interval stated?

Please let me know if you need further help.

Katherine