Step-by-step explanation:
sin ∅ + 1 = cos2∅
From multiple angles in trigonometry
cos2∅ = 1 - 2sin²∅
So we have
sin∅ + 1 = 1 - 2sin²∅
sin∅ +1 - 1 + 2sin²∅= 0
sin∅ + 2sin²∅ = 0
Factor out sin∅
sin∅ ( 1 + 2sin∅) = 0
sin ∅ = 0
∅ = 0° , 180°
1 + 2sin∅ = 0
2sin∅ = - 1
sin ∅ = -1/2
∅ = 210° , 330°
The solutions are
0° , 180° , 210° , 330°
Hope this helps you
