Buktikan identitas trigonometri berikut: (1-cos a) (1+sec a) = sin a .Tan a

(1 - cos a) (1 + sec a) = sin a. tan a
(1 - cos a) (1 + 1/cos a) = sin a . tan a
(1 - cos a) ((cos a + 1)/cos a) = sin a . tan a
(1 - cos a) (1 + cos a) = sin a. tan a. cos a
1 - cos^2 a = sin a. (sin a / cos a) . cos a
(sin^2 a + cos^2 a) - cos^2 a = sin^2 a
sin^2 a = sin^2 a

TERBUKTI!

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