Chứng minh 2x > x
Chứng minh 2x > x
Xét 3 trường hợp:
x=0 => 20=1=> x2>x
\(x\in\left\{Z-N-0\right\}\)=> 2x=\(\frac{1}{2^{-x}}\)=> 2x>x
\(x\in N\)=> 2x>x
4\(^{2x+\sqrt{x+2}}\)+2\(^{x^3}\)=4\(^{2+\sqrt{x+2}}\)+2\(^{x^3+4x-4}\)
3^x>6 vậy x= mấy
\(9^{-x}+9^x+3\left(3^{-x}+3^x\right)\le8\)