To evaluate the given expression, recall that for any positive number n its factorial is defined as n!=n(n-1)(n-2)...(3)(2)(1).
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Practice makes perfect
We want to evaluate the given expression. To do so, let's recall the definition of the factorial of a positive integer n.
n!=n(n-1)(n-2)... (3)(2)(1)
With the above definition in mind, we can simplify the given expression.
