# recursive algorithm to determine C(n,r).

**Question description**

Suppose C(n,r) denotes the number of ways r different things can be chosen from a set of n items. Then C(n,r) is given by the following formula:

where the exclamation point denotes the factorial function. Moreover, It is known that

Write a recursive algorithm to determine C(n,r). Identify the base case(s) and the general case(s).

Using your recursive algorithm, determine C(5,3) and C(9,4).

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