1.已知x=10,求1/x-1+1/(x-1)(x-2)+1/(x-2)(x-3)+1/(x-3)(x-4)+1/(x-4)(x-5)的值 1/(x-1)(x-2)=1/(x-1)-1/(x-2) 1/(x-2)(x-3)=1/(x-2)-1/(x-3) 1/(x-3)(x-4)=1/(x-3)-1/(x-4) 1/(x-4)(x-5)=1/(x-4)-1/(x-5) 原式=1/x-...