Question

1乘5乘3分之4加3乘5乘7加...加95乘97乘99分之4

Answer 1

=[1/(1*3)-1/(3*5)]+[1/(3*5)-1/(5*7)]+.+[1/(95*97)-1/(97*99)]

=1/(1*3)-[1/(3*5)-1/(3*5)]-.-[1/(95*97)-1/(95*97)]-1/(97*99)

=1/3-0-0-.-0-1/(97*99)

=3200/9603