[tex]2x\sqrt{1-2y^2}+2y\sqrt{2}\sqrt{2-3z^2}+2z\sqrt{3}\sqrt{5-x^2}=8\leqslant x^2+1-2y^2+2y^2+2-3z^2+3z^2+5-x^2=8[/tex]
dấu "=" xảy ra khi [tex]\left\{\begin{matrix} x=\sqrt{1-2y^2} & & \\ \sqrt{2}y=\sqrt{2-3z^2} & & \\ \sqrt{3}z=\sqrt{5-x^2}& & \end{matrix}\right.=>x^2+2y^2+3z^2=8-(x^2+2y^2+3z^2)=>x^2+2y^2+3z^2=4[/tex]