5. Consider the following function fn. 1. Compute the value f(n(5). Show the steps in your computation. [4 marks] 2. Illustrate all recursive calls made by the algorithm on input n=4, i.e., when calling fn(3), by drawing the recursion tree. [4 marks] 3. What does f(n(n) compute for n1 ? You do not need to justify your answer. [4 marks] 4. Compute an estimate of the execution time as a function of n. Give your answer in Big-Oh notation and justify your answer. [4 marks]