Re: [計量] 幾題數學~~
※ 引述《butini (hackneyed)》之銘言：
: 救我的排列組合= =太爛了
: Test 5
: 10. Set X has x members and set Y has y members. Set Z i s composed of all
: members that are in either set X or set Y with the exception of the k common
: members (k>0).Which of the follow ing represents the numbers in set Z?
: *看不懂k代表什麼? Ans: x+y-2k
: Test 7
: 1.Each person at a party shook hands exactly once with each other at the
: party. There was a total of 21 handshacks exchanged at the party.
: Column A: the number of people at the part.
: Column B: 8
: *我算7 選A 可是答案是B..
: 20.Four boys and three girls are arranged seatts in two rows, the first
: containing four seats and the second three seats. How many possible
: arrangements are there if the boys and the girls sit next to each other?
: Ans: 288
: 21. 同題20. How many arrangements are there if three girls sit together?
: Ans:840
: Test 8
: 6.x+y+z<0 z>x+y+1
: Column A: z
: Column B:1
: Ans:D
: *有判斷的好方法嗎
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
x+y+z<0 ==>-z>x+y----(1)
並且 z>x+y+1-----(2)
(2)-(1)得: 2z>1 ==>z>1/2跟1比.Z可以比1小.可以等於1.也可以比1大.so.無法判
斷.選D
: 8. On the real number line, the coordinate of points A, B, and C are 2, -1
: and x, respectively. What is value of x when line AC^2 + line BC^2 has
: the least value?
: Ans: 1/2
: 21. If 5 cards, represented by A, B, C, D, and E, are placed in a row
: so that C is never at either end, how many different arrangements
: are possible?
: Ans:72
: 我算96耶@@ 全部有5!種=120 C在最後面有4!種=24 120-24=96
: 那邊錯了??
: 22. How many possible committees can be formed from a group of seven people
: if each committee can have any numbers from one to seven?
: Ans: 127
: Test 9
: 10. Which of the following is the second power of (1+1^0.5)^0.5
: Ans: 2^0.5
: *second power是什麼?
: 24. A bag contatins red gloves, black gloves and white ones.
: What is the least number of gloves that must be taken out of the bag
: to be sure of having 4 pairs of gloves?
: Ans:10
: *不懂
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06/17 22:01, , 1F
06/17 22:01, 1F
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