Jawab:
1 + tan²x = 1 + sin²x/cos²x ₓ cos² x
tan x sinx/cosx cos² x
= cos² x + sin² x
sinx cosx
= 1 ₓ 1
sin x cos x
= cosec x sec x
Jadi, 1 + tan² x/tan x = cosec x sec x