{"id":3604,"date":"2021-08-01T09:09:18","date_gmt":"2021-08-01T09:09:18","guid":{"rendered":"https:\/\/mathemerize.com\/?p=3604"},"modified":"2021-11-27T22:11:51","modified_gmt":"2021-11-27T16:41:51","slug":"formula-for-circular-permutation","status":"publish","type":"post","link":"https:\/\/mathemerize.com\/formula-for-circular-permutation\/","title":{"rendered":"What is the Formula for Circular Permutation ?"},"content":{"rendered":"
Here, we will learn circular permutation and the formula for circular permutation with examples.<\/p>\n
Let’s begin –<\/p>\n
If there are 4 different things, then for each circular arrangement number of linear arrangement is 4.<\/p>\n
Similarly, if n different things are arranged along a circle, for each circular arrangements number of linear arrangement is n.<\/p>\n
Therefore, the number of linear arrangements of n different things is n \\(\\times\\) (number of circular arrangements of n different things). Hence the number of circular arrangements of n different things is –<\/p>\n
\n\\(1\\over n\\) \\(\\times\\) (number of linear arrangements of n different things) = \\(n!\\over n\\) = \\((n – 1)!\\)<\/p>\n<\/blockquote>\n
Formula :<\/h2>\n
therefore note that, the formula for circular permutation is –<\/p>\n
(i) The number of circular permutation of n different things taken all at a time is:<\/p>\n
\n(n – 1)!<\/p>\n<\/blockquote>\n
If the clockwise and anticlockwise circular permutations are considered to be same, then it is:<\/p>\n
\n\\((n – 1)!\\over 2\\)<\/p>\n<\/blockquote>\n
(ii) Number of circular permutations of n different things taking r at a time distinguishing clockwise and anticlockwise arrangements is :<\/p>\n
\n\\(^{n}P_r\\over r\\)<\/p>\n<\/blockquote>\n\n\n
Example : <\/span> A person invites a group of friends at dinner. They sit
\n(i) 5 on one round table and 5 on other round table
\n(ii) 4 on one round table and 6 on other round table
\nFind the number of ways in each case in which he can arrange the friends.<\/p>\nSolution : <\/span>(i) The number of ways of selection of 5 friends for the first table is \\(^{10}C_5\\). Remaining 5 friends are left for the second table.
\nThe total number of permutation of 5 friends at a round table is 4!. Hence, the total number of arrangements is \\(^{10}C_5\\) \\(\\times\\) 4! \\(\\times\\) 4!
\n \t\t (ii) The number of ways of selection of 6 friends is \\(^{10}C_6\\). Remaining 4 friends are left for the second table.
\nThe number of ways of permutation of 6 friends at a round table is 5!. The number of ways of 4 friends at a round table is 3!
\nHence, the total number of arrangements is \\(^{10}C_6\\) \\(\\times\\) 5! \\(\\times\\) 3!
<\/p>\n\n\nHope you learnt the formula for circular permutation, learn more concepts of permutation and combination and practice more questions to get ahead in the competition. Good luck!<\/p>\n\n\n