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#1 2008-04-18 00:18:42
- chetah
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- Registered: 2008-02-15
- Posts: 32
Permutations
P(n,2) = 90. What is n?
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#2 2008-04-18 00:35:04
- mathsyperson
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- Registered: 2005-06-22
- Posts: 4,900
Re: Permutations
P(n,2) = n!/(n-2)! = n(n-1).
Now you can make a quadratic and solve it.
Why did the vector cross the road?
It wanted to be normal.
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