It is sometimes useful to have a closed-form definition instead; for this purpose, an approximation can be used. R.W. Gosper proposed the following approximation formula: n! z n'en 2n + TT Create a function takes n as input and returns the approximation for factorial value. This program is written in C Use C loop control statements while and for In your function for finding the approximation. Define Pl as a constant macro #define PI 3.14159265