Question

How do you prove `(1-cosx)(1+secx)=sinxtanx`?

Answer 1

#f(x) = (1 - cos x)(1 + 1/cos x) = (1 - cos x) (cos x + 1)/cos x = (1 - cos^2 x)/cos x = sin^2 x/cos x = sin x*(sin x/cos x) = sin x*tan x#

Reminder:
`(1 - cos x)(1 + cos x) = (1 - cos ^2 x) = sin^2 x`