1. Write a C code to find the sum of the following series using RECURSIVE FUNCTIONS: 12 +22+ 32 + ... + N 2. Write a C program using recursive function to find the inverse product of 1st n natural numbers. E.g. for n= 5, the function should return (1/5) * (1/4) *(1/3) * (1/2) *(1/1) = 1/120 =0.00833 3. Compute the value of ab using recursion, where a and b are integers. 4. Write a C program to print all natural numbers from n to 1 (i.e., from upper to lower) using recursion.