How do you prove sin(x+(π/2))=cosx?
Using just these formulas.
Using just these formulas.
1 Answer
Mar 2, 2018
There are 2 ways:
1. Use trig identity:
sin (a + b) = sin a.cos b + sin b.cos a
In this case
sin (x + pi/2) = sin x.cos (pi/2) + sin (pi/2).cos x.
Because cos (pi/2) = 0; and sin (x/2) = 1, therefor,
2. By the unit circle.