Respuesta :
Rule of trigonometric functions:-
sin a = cos(90 - a)
Here a = 90°.
sin 90 = cos (90 - 90)
1 = cos 0.
cos 0 = 1.
So the cos 0 = 1.
Answer:
Step-by-step explanation:
If sin 90 = 1
then cos 0 will be
as we know that
cosx = sin(90-x)
If we plug x = 0 ,
cos0 = sin 90 = 1
