whongaliemtan x - (sec² / tan x) = (tan² x - sec² x) / tan x = { (sec² x - 1) - sec² x } / tan x = (sec² x - 1 - sec² x) / tan x = - 1 / tan x = - cotan x
{cos x /(1 + sin x) } + {(1 +sin x) /cos x } = {cos² x + (1 + sin x)²} /cos x (1 + sin x) = ( cos² x + 1 + 2sin x + sin² x) / cos x (1 + sin x) = (1 + 1 + 2sin x) / (cos x (1 + sin x) = (2 + 2 sin x) / cos x (1 + sin x) = 2 (1 + sin x) / cos x (1 + sin x) = 2 / cos x = 2.sec x
= { (sec² x - 1) - sec² x } / tan x
= (sec² x - 1 - sec² x) / tan x
= - 1 / tan x
= - cotan x
{cos x /(1 + sin x) } + {(1 +sin x) /cos x } = {cos² x + (1 + sin x)²} /cos x (1 + sin x)
= ( cos² x + 1 + 2sin x + sin² x) / cos x (1 + sin x)
= (1 + 1 + 2sin x) / (cos x (1 + sin x)
= (2 + 2 sin x) / cos x (1 + sin x)
= 2 (1 + sin x) / cos x (1 + sin x)
= 2 / cos x
= 2.sec x