buktikan identitas trigonometri berikut! 1.) tan x + cot x = sec x . csc x 2.) (sec a + tan a) (sec a - tan a) = 1

1. tan x + cot x
= (sinx/cos x) + (cos x/ sin x)
= (sin^2 x + cos^2 x) / cos x × sin x
= 1/(cos x × sin x)
= (1/cos x) × ( 1/sin x)
= sec x . csc x (terbukti)

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