Question

初二数学B卷第26道填空题

Answer 1

= 1/(x+1) - 1/(x+2) + 1/(x+2) - 1/(x+3) +...+ 1/(x+4) - 1/(x+5)

= 1/(x+1) - 1/(x+5)

= 4/{(x+1)(x+5)}