Question

1/1*2*3+1/2*3*4+..........+1/98*99*100

Answer 1

\(\frac{99}{100}\)

tick mình nha 

Hoàng Công Hậu 52 ☺♥☻

Answer 2

Ta có:

1/1*2*3+1/2*3*4+...........+1/98*99*100

=4/4*(1/1*2*3+1/2*3*4+...........+1/98*99*100)

=1/4*(1/1*2*3*4+1/2*3*4*4+...........+1/98*99*100*4)

=1/4*[1/1*2*3*4+1/2*3*4*(5-1)+............+1/98*99*100*(101-97)]

=1/4*(1/1*2*3*4+1/2*3*4*5-1/1*2*3*4+..........+1/98*99*100*101-1/97*98*99*100)

=1/4*1/98*99*100*101

=1/4*1/97990200

=1/391960800

Vậy 1/1*2*3+1/2*3*4+...........+1/98*99*100=1/391960800

Tick nha