Question

解方程：1乘2分之X+2乘3分之X+.+99乘100分之X=99

Answer 1

1/(1*2)=1-1/2,

1/(2*3)=1/2-1/3,

.

1/(98*99)=1/98-1/99,

1/(99*100)=1/99-1/100,

1/(1*2)+1/(2*3)+.+1/(99*100)

=1-1/100

=99/100,

x*[1/(1*2)+1/(2*3)+.+1/(99*100)]

=99x/100,

99x/100=00,

x=100.