Question

A+b=270° maka cos a + sinB =

Answer 1

Anggaplah:
b = 270° - a
Sehingga:
cos a + sin b
= cos a + sin(270° - a)

Sifat trigonometri:
sin(270°-a) = cos(90° - (270°-a))
sin(270°-a) = cos(a - 180°)
sin(270°-a) = -cos a

Sehingga:
= cos a + sin(270° - a)
= cos a + (-cos a)
= cos a - cos a
= 0

Answer 2

a + b = 270'
a        = 270' - b

cos a + sin b , ganti a menjadi 270' - b