Combinations Permutations Nasıl Hesaplanır?
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Combinations count ways to choose items where order does not matter. Permutations count ways where order does matter. Both use factorials and appear in probability, statistics, and combinatorics.
Adım Adım Kılavuz
- 1Permutations (order matters): P(n,r) = n! / (n−r)!
- 2Combinations (order irrelevant): C(n,r) = n! / (r!(n−r)!)
- 3Rule of thumb: if you can swap two items and get a different result, use permutations
Çözümlü Örnekler
Giriş
Choose 3 from 10 (order matters)
Sonuç
720
P(10,3) = 10×9×8 = 720
Giriş
Choose 3 from 10 (order irrelevant)
Sonuç
120
C(10,3) = 720/6 = 120
Giriş
Lotto: 6 from 49
Sonuç
13,983,816
C(49,6)