Question

evaluate the expression 9p9. 9p9 =

Explanation:

Step1: Recall permutation formula

The permutation formula is \(_{n}P_{r}=\frac{n!}{(n - r)!}\). Here \(n = 9\) and \(r=9\).

Step2: Substitute values into formula

Substitute \(n = 9\) and \(r = 9\) into the formula: \(_{9}P_{9}=\frac{9!}{(9 - 9)!}=\frac{9!}{0!}\).

Step3: Use factorial and \(0!\) value

Since \(0!=1\) and \(n!=n\times(n - 1)\times\cdots\times1\), then \(9!=9\times8\times7\times6\times5\times4\times3\times2\times1 = 362880\). So \(_{9}P_{9}=\frac{9!}{1}=9!\).

Answer:

\(362880\)