Question

1. evaluate Sin 18° and cos 18
sos 18 = lotos
Sen 16 = 15-1
4
4
then
Sin 18°
Sin 36°.
X
sensya
Cossy
X
Sin 72o.
Cordre
Cos 18°
Conso x
du​

Answer 1

Answer:

Let A = 18°. Therefore, 5A = 90°. ⇒ 2A + 3A = 90˚. ⇒ 2θ = 90˚ - 3A. Taking sine on both sides, we get. sin 2A = sin (90˚ - 3A) = cos 3A. ⇒ 2 sin A cos A = 4 cos^3 A ...

Step-by-step explanation:

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