1/1X2+2/1X2X3+3/1X2X3X4+4/1X2X3X4X5+5/1X2X3X4X5X6+6/1X2X3X4X5X6X7

Question

如题所述

Answer 1

1/1*2+2/1*2*3+3/1*2*3*4+4/1*2*3*4*5+5/1*2*3*4*5*6+6/1*2*3*4*5*6*7
=1-1/1*2+1/1*2-1/1*2*3+1/1*2*3-1/1*2*3*4+1/1*2*3*4-1/1*2*3*4*5+1/1*2*3*4*5-1/1*2*3*4*5*6+61//1*2*3*4*5*6-1/1*2*3*4*5*6*7
=1-1/1*2*3*4*5*6*7
=1-1/5040
=5039/5040希望能帮到你祝学习进步哦！本回答被网友采纳

Answer 2

5039/5040

Answer 3

1/1*2+2/1*2*3+3/1*2*3*4+……+9/1*2*…*10

=1-1/2+(1/1*2-1/2*3)+(1/1*2*3-1/2*3*4)+....+(1/1*2*3*...9-1/2*...10)

=1-1/2*3...10

=1-1/3628800

=3628799/3628800