Question

计算11/8+1/24+1/48+1/80+1/120

Answer 1

1/8+1/24+1/48+1/80+1/120

=1/(2×4)+1/(4×6)+1/(6×8)+1/(8×10)+1/(10×12)

=1/2×(1/2-1/4)+1/2×(1/4-1/6)+1/2×(1/6-1/8)+1/2×(1/8-1/10)+1/2×(1/10-1/12)

=1/2×(1/2-1/4+1/4-1/6+1/6-1/8+1/8-1/10+1/10-1/12)

=1/2×(1/2-1/12)

=1/2×5/12

=5/24

明白请采纳,

有新问题请求助,