ta có
$y'=x'.\sqrt[]{4-x^2}+(\sqrt[]{4-x^2})'.x$
$y'=1.\sqrt[]{4-x^2}+\dfrac{(4-x^2)'}{2\sqrt[]{4-x^2}}.x$
$y'=\sqrt[]{4-x^2}+\dfrac{-x^2}{\sqrt[]{4-x^2}}$
$y'=\dfrac{4-x^2}{\sqrt[]{4-x^2}}+ \dfrac{-x^2}{\sqrt[]{4-x^2}} $
$y'=\dfrac{4-x^2-x^2}{\sqrt[]{4-x^2}}$
$y'=\dfrac{4-2x^2}{\sqrt[]{4-x^2}}$
xin hay nhất nhé
$duynghia69@$