Answer:
To see the function graph and check its behavior; see the location of the points its zeros and extract some other information, like doing the Horizontal line Test on the graph.
Explanation:
Because instead of representing a function with words, or as a correspondence between sets, or even as a table, We might want to represent it in the analytical form to see the function graph and check its behavior; see the location of the points its zeros and extract some other information, like doing the Horizontal line Test on the graph.