How do you differentiate cosx1sinx?

1 Answer
Jun 13, 2016

Quotient Rule:-

If u and v are two differentiable functions at x with v0, then y=uv is differentiable at x and

dydx=vduudvv2

Let y=cosx1sinx

Differentiate w.r.t. 'x' using quotient rule

dydx=(1sinx)ddx(cosx)cosxddx(1sinx)(1sinx)2

Since ddx(cosx)=sinx and ddx(1sinx)=cosx

Therefore dydx=(1sinx)(sinx)cosx(cosx)(1sinx)2

dydx=sinx+sin2x+cos2x(1sinx)2

Since sin2x+cos2x=1

Therefore dydx=1sinx(1sinx)2=11sinx

Hence, derivative of the given expression is 11sinx.