Combinatorics Symbols
| Symbol | Symbol Name | Meaning/Definition | Example |
|---|---|---|---|
| \( n! \) | factorial | \( n!= n \cdot (n − 1) \cdots 3 \cdot 2 \cdot 1 \) | \( 5!=5\cdot 4\cdot 3\cdot 2\cdot 1 = 120 \) |
| \( ^nP_k \) | permutation | \( ^nP_r = \frac {n!}{(n-r)!} \) | \( ^4P_3 = \frac {4!}{(4-3)!}=24 \) |
| \( ^nC_k \) | combination | \( ^nC_r= \frac {n!}{(n-r)!r!} \) | \( ^5C_3= \frac {5!}{(5-3)!3!}= 10 \) |
