\(0\le x,y,z\le1\Rightarrow x^{10}\le x;y^6\le y;z^{2016}\le z;0\le xyz\le1\)

CÓ: \(\left(1-x\right)\left(1-y\right)\left(1-z\right)\ge0\)

=>\(1-xyz+\left(xy+yz+zx\right)-\left(x+y+z\right)\ge0\)

=>\(x+y+z-xy-yz-zx-xyz\le1\)

=>\(x^{10}+y^6+z^{2016}-xy-yz-zx\le1\)

Dấy "=" xảy ra <=> trong 3 số x,y,z có 1 số bằng 0, 2 số bằng 1 hoặc 1 số bằng 1, 2 số bằng 0

\(\frac{1}{\sqrt{x}+1}\)><

\(ĐKXĐ:x\ge0\)

\(\left(\frac{2}{2-\sqrt{x}}+\frac{3+\sqrt{x}}{x-2\sqrt{x}}\right):\left(\frac{2+\sqrt{x}}{2-\sqrt{x}}-\frac{2-\sqrt{x}}{2+\sqrt{x}}-\frac{4x}{x-4}\right)\)

\(=\frac{-2\sqrt{x}}{x-2\sqrt{x}}:\frac{\left(2+\sqrt{x}\right)^2-\left(2-\sqrt{x}\right)^2+4x}{4-x}\)

\(=\frac{-2\sqrt{x}}{x-2\sqrt{x}}:\frac{\left(4+4\sqrt{x}+x\right)-\left(4-4\sqrt{x}+x\right)+4x}{4-x}\)

\(=\frac{-2\sqrt{x}}{x-2\sqrt{x}}:\frac{8\sqrt{x}+4x}{4-x}\)

\(=\frac{-2\sqrt{x}}{x-2\sqrt{x}}.\frac{4-x}{8\sqrt{x}+4x}\)

\(=\frac{2\sqrt{x}\left(\sqrt{x}-2\right)\left(2+\sqrt{x}\right)}{\sqrt{x}\left(\sqrt{x}-2\right).2\sqrt{x}\left(4+2\sqrt{x}\right)}\)

\(=\frac{\left(2+\sqrt{x}\right)}{\sqrt{x}\left(4+2\sqrt{x}\right)}=\frac{1}{2\sqrt{x}}\)

mk ko kt lại nên sai từ dòng 2 r, bạn cộng thêm (3+căn x) vào r giải tương tự

\(\frac{a}{b^2+1}=a-\frac{ab^2}{1+b^2}\ge a-\frac{ab^2}{2b}\ge a-\frac{ab}{2}\)  (AM-GM)

chung minh tuong tu ta co 

\(VT\ge a+b+c-\frac{ab}{2}-\frac{bc}{2}-\frac{ac}{2}\ge3-\frac{\left(a+b+c\right)^2}{6}\ge3-\frac{3}{2}=\frac{3}{2}\)

dau = xay ra khi a=b=c=1