please provide multiple sentences in detail for each question.. its for a dba

What is the definition of function? Discuss the different ways of representing a function with examples of your own.

Provide an example of a function that does not have an inverse function. How do you prove that it is not a function?

Find the inverse of the function y = 3 square root of x over 3 minus 1 and explain the process.

Provide a real-life application of a composition of functions.

Create a function with a domain of all real numbers and the range all real numbers that are greater than or equal to zero. Provide the function both graphically and in function notation.