Question

Derivata din f(x)= sinx- xcosx/cosx+ xcosx ?

Answer 1

Salut,

$f^{'}(x)=\dfrac{(sinx-xcosx)^{'}\cdot(cosx+xsinx)-(sinx-xcosx)\cdot(cosx+xsinx)^{'}}{(cosx+xsinx)^2}=\\\\=\dfrac{[cosx-(cosx-xsinx)]\cdot(cosx+xsinx)-(sinx-xcosx)\cdot(-sinx+sinx+xcosx)}{(cosx+xsinx)^2}=\\\\=\dfrac{xsinx\cdot(cosx+xsinx)-(sinx-xcosx)\cdot xcosx}{(cosx+xsinx)^2}=\dfrac{x^2}{(cosx+xsinx)^2}.$

Green eyes.

Answer 2

Cea gresita dadea o forma foarte lunga.