關於permuation of repitation

kennis

2006-12-29 11:33 am

我自己take 左notes, 但現在睇返都唔係幾明自己寫乜

Permutation of repitation 's formula :
n! / n! n! n!

then我仲寫左, 當 n咁多樣野放出黎既時侯, 有 r, s, y 的種類. 而放出來的時侯不會重複, 哩個算係例子一個la...
咁係唔係即係
n! / r! s! y! ??

回答 (2)

myisland8132

2006-12-29 1:49 pm

✔ 最佳答案

你0的notes符號有些亂﹐我係到直接寫番個正確既answer
Permutations with Repetition:

The number of different permutations of n objects, where there are n1 indistinguishable objects of style 1, n2 indistinguishable objects of style 2, ..., and nk indistinguishable objects of style k, is ;

圖片參考：http://www.regentsprep.org/Regents/math/ALGEBRA/APR2/LpermR8.gif

Example:
1. How many different 5-letter words can be formed from the word APPLE ?
answer
5!/2!=120/2=60
2! because the letter P repeats twice.

2. How many different six-digit numerals can be written using all of the following six digits:
4,4,5,5,5,7

answer
6!/2!3!=720/12=60

Two four and three fives repeat, so divide by 2! and 3!

參考: http://www.regentsprep.org/Regents/math/ALGEBRA/APR2/LpermRep.htm

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Hooligan

2006-12-29 12:43 pm

完全唔知你寫乜... 我讀緊maths master都唔知你想點

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