計算：(1＋1/2＋1/3＋1/4)x(1/2＋1/3＋1/4＋1/5)-(1＋1/2＋1/3＋1/4＋1/5)x(1/2＋1/3＋1/4) = ？
2005-11-19 02:58:13 · 3 個解答 · 發問者 Frank 7 in 科學 ➔ 數學
(1＋1/2＋1/3＋1/4)x(1/2＋1/3＋1/4＋1/5)-(1＋1/2＋1/3＋1/4＋1/5)x(1/2＋1/3＋1/4) =
(1+1/2+1/3+1/4)x(1/2＋1/3＋1/4＋1/5)-(1＋1/2＋1/3＋1/4)x(1/2＋1/3＋1/4)-1/5x(1/2＋1/3＋1/4)
=(1＋1/2＋1/3＋1/4)x(1/2＋1/3＋1/4＋1/5-(1/2＋1/3＋1/4))-1/5x(1/2＋1/3＋1/4)
=(1＋1/2＋1/3＋1/4)x1/5-1/5x(1/2＋1/3＋1/4)
=1/5
2005-11-19 03:13:05 · answer #1 · answered by Anonymous · 0⤊ 0⤋
深呼吸~~~~衝啊!!!
2005-11-19 04:00:21 · answer #2 · answered by 沒有 1 · 0⤊ 0⤋
(1＋1/2＋1/3＋1/4)x(1/2＋1/3＋1/4＋1/5)-(1＋1/2＋1/3＋1/4＋1/5)x(1/2＋1/3＋1/4)
=(12/12＋6/12＋4/12＋3/12)ｘ(30/60＋20/60＋15/60＋12/60)－(60/60＋30/60＋20/60＋15/60＋12/60)ｘ(30/60＋20/60＋15/60)
=25/12ｘ77/60－137/60ｘ65/60
↓ ↓
5/12ｘ77/12－137/60ｘ13/12
=385/144－1781/720
=1925/720－1781/720
=144/720
=1/5
2005-11-19 03:34:00 · answer #3 · answered by Anonymous · 0⤊ 0⤋