原式=a+2a+3a+…10a+b+b/2*3+…b/9*10 =a(1+2+3+…10）+b(1+1/2*3+1/3*4+…+1/9*10) =[(1+10)*10/2]*a+b*(1+1/2-1/3+1/3-1/4+1/4-1/5+…1/8-1/9+1/9-1/10) =55a+b*(1+1/2-1/10) =55a+7b/5是的1/2*3=1/6还是3/2如果是...