(x-1)x分之1+x(x+1)分之1+(x+1)(x+2)分之1+(x+2)(x+3)分之1=1/(x-1)- 1/x + 1/x - 1/(x+1) .+ 1/(x+2) - 1/ (x+3)= 1 / (x-1) - 1/ (x+3)= ( x-3-x+1 ) /(x-1) (x+3)= -2 /(x-1) (x+3)施主,我看你骨骼清奇,器宇轩昂,...