sec^4B (1-sin^4B) = 1 + 2tan^2B Tolong ya terimakasih

Kelas 10 Matematika
Bab Trigonometri

sec⁴ B (1 - sin⁴)
= (1/cos⁴ B) . (1 - sin² B) . (1 + sin² B)
= (1/cos² B) . (1/cos² B) . cos² B . (1 + sin² B)
= (1 + sin² B)/cos² B
= (1/cos² B) + (sin² B/cos² B)
= sec² B + tan² B
= 1 + tan² B + tan² B
= 1 + 2 . tan² B

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