sec x का अवकल गुणांक ज्ञात कीजिये

Explanation

माना कि `cos x = t .` तब
`d/dx (sec x) = d/dx (cos x)^(1) = d/dt (t)^(-1) [dt/dx] = -t^(-2) d/dx (cos x ) `
`=-sec^(2) x (-sin x ) = sec x tan x .`