這個(gè)應(yīng)該是題目做法解析吧,但前一個(gè)和后一個(gè)都有不全的地方.I wonder why……
大意為：
14.一個(gè)中學(xué)搞足球比賽,每個(gè)隊(duì)只跟別的每一個(gè)隊(duì)比賽一次.如果在2012賽季總共比了21次,請(qǐng)問有多少個(gè)隊(duì)參加了這次比賽?
（14.In the,a middle school football conference,each team plays every other team exactly once.If a total of 21 conference games were played during the 2012 season,how many teams were members of the BIG N conference?）
這個(gè)問題和握手問題非常相似.我們常用這個(gè)公式去找出比賽的次數(shù)（或是握手的）.現(xiàn)在我們反著用這個(gè)公式.
因此我們有了這個(gè)方程的解,我們解出隊(duì)伍的數(shù)量為 （為什么就沒了啊!）
（This problem is very similar to a handshake problem.We use the formula to usually find the number of games played (or handshakes).Now we have to use the formula in reverse.
So we have the equation Solving,we find that the number of teams in the BIG N conference is .）
14.14.在BIG.N中,一個(gè)中學(xué)搞足球比賽,每個(gè)隊(duì)只跟別的每一個(gè)隊(duì)比賽一次.如果在2012賽季總共比了21次,請(qǐng)問有多少個(gè)隊(duì)參加了這次比賽?
（14.In theBIG N,a middle school football conference,each team plays every other team exactly once.If a total of 21 conference games were played during the 2012 season,how many teams were members of the BIG N conference?）
這個(gè)問題跟握手問題非常相似.我們常用公式n(n-1)/2去找比賽的次數(shù).現(xiàn)在我們反著用這個(gè)公式.n(n-1)/2=21