(1) f(x) = (1 + lnx)x⁻¹ f'(x) = (1/x)x⁻¹ + (1+lnx)(-1)x⁻² = -x⁻²lnx x ≥1时,lnx ≥0,x⁻² > 0,f'(x) ≤ 0,减函数(2) 令g(x) = (x+1)f(x) = x⁻
...