## Calculus Concepts: An Informal Approach to the Mathematics of Change 5th Edition

This is because for every $x$ value, there is only one $y$ value. For further information, it is nearly impossible to deduce what function that is, however, it passes the straight line test for all values $x$. (The straight line test is a straight vertical line that, if passes through two points, proves that the graph tested is not a function).