Chapter 4

In chapter four we learned about functions and how to find their inverses, symmetry, and if they were functions at all.

Finding out if a function is a function at all involves the use of the vertical line test.

When you graph a function; if you can draw a vertical line and have it hit two points at any part of the graph, it's not a function.

The function f(x)=x^2 + 4 would be a function since there's no point on the graph where a vertical line would hit a x point twice.

The graph x=2 is not a function because a vertical line hits all the points on the graph.

Finding a function's inverse

If a function has an inverse, a horizontal line will not be able to touch any two points of the graph.

The graph f(x)= x+3 has an inverse because a horizontal line would cross its graph once.

The graph f(x)=x^2-5 wouldn't have an inverse that is also a function because a horizontal line can touch the graph twice.