设 x1 x2 ∈(1,正无穷) 且 x1>x2则f(x1)-f(x2)=1+1/(x1-1)-1-1/(x2-1)=1/(x1-1)-1/(x2-1)=(x2-1-x1+1)/[(x1-1)(x2-1)]=(x2-x1)/[(x1-1)(x2-1)]因为 x1>1 x2>1所以 (x1-1)>0 (x2-1)>0得 (1-x1)(1-x2)>0又 x1>x2所以 x...