What is the derivative of (cot^(2)x)?

1 Answer
Jan 9, 2016

frac{d}{dx}(cot^2x) = frac{-2cosx}{sin^3x}

Explanation:

frac{d}{dx}(cot^2x) = 2cot(x)*frac{d}{dx}(cotx)

= 2cotx*frac{d}{dx}(cosx/sinx)

= 2cotx*frac{sinxfrac{d]{dx}(cosx)-cosxfrac{d}{dx}(sinx)}{sin^2x}

= 2cotx*frac{sinx(-sinx)-cosx(cosx)}{sin^2x}

= 2cotx*frac{-(sin^2x+cos^2x)}{sin^2x}

= 2frac{cosx}{sinx}*frac{-1}{sin^2x}

= frac{-2cosx}{sin^3x}