20．已知函数f(x)=ex−e−x+1f(x)=e^{x}-e^{-x}+1f(x)=ex−e−x+1，则关于xxx的不等式f(2x−1)+f(x+1)>2f(2x-1)+f(x+1)>2f(2x−1)+f(x+1)>2的解集为 ___(0,+∞)(0,+\infty )(0,+∞)___．