n! (n -k and combinations 3. Write a program. to compute the permutations n P, na = k!(n-k) using recursive functions for the following three pairs of n and k: b) (n, k) = (8,3). c) (n, k) = (7,4). [9 points] 4. Write a program that calculates how many digits a number contains. Assume that the number has no more than four digits. [Hint: Use if statements to test the number.] [8 points] For example: Enter a number: 526 The number 526 has 3 digits