Question

Buktikan Identitas Trigonometri No 24,25 .

Answer 1

Verified answer

24.

samakan penyebutnya --> (1 - sin x)(1 + sin x) = 1 - sin² x = cos ²x

1/(1 - sin x) + 1/(1 + sin x)
= ((1 + sin x) + (1 - sin x))/cos² x
= 2/cos² x
= 2 sec² x
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25.
Pembilang = a = (1 - sin² A) - sin A + sin³ A
a = cos² A - sin A(1 - sin² A)
a = cos² A (1 - sin A)

Penyebut = b = cos A - sin A cos A
b = cos A (1 - sin A)

Soal
a/b
= cos² A (1 - sin A) / cos A (1 - sin A)
= cos A
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