Answer:
a = 60° or π/3
Step-by-step explanation:
Given :-
sin² a/2 - sin a/2 + 1/4
To find :-
a
Solving :-
sin² a/2 - sin a/2 + 1/4 = (sin a/2 - 1/2)² = 0
sin a/2 - 1/2 = 0
sin a/2 = 1/2
a/2 = 30°
Solution :-
