Exercise 1 The following set of short questions will focus on getting you familiar with how to write PHP functions as well as how to make use of the pre-existing PHP functions. All your PHP functions must be declared in the document body section and each functions name must be as specified below. To demonstrate the functionality of each method, you must make function calls in the document body. Include a heading(hl h6) that indicates which function is being tested before each function demonstration. The use of Global Variables is forbidden! Test all your functions with some relevant input parameter values. A. Function: computefactorial Parameter(s): Number Given the number, find its factorial and return it. If the parameter is not an integer number or if it is a negative number, return false