4.3 Reading Graphs of Functions
Notes
Graphs show how a function behaves.
- The $y$-intercept is where the graph crosses the $y$-axis (where $x = 0$). An $x$-intercept (or zero) is where it crosses the $x$-axis (where $y = 0$).
- A function is increasing where its graph rises from left to right and decreasing where it falls.
- A maximum is the highest point; a minimum is the lowest point.
- In context, read the axis labels and units.
Practice
A graph crosses the $x$-axis at $(4, 0)$. That point is called:
It is where the output is 0.
The height of a ball is graphed against time. The graph rises, peaks at (2, 20), then falls. What does (2, 20) mean?
The peak is the maximum height.
On which interval is a function decreasing if its graph falls from $x = -3$ to $x = 1$ and rises after that?
It falls between those $x$-values.
Ready for more? Take the Unit 4 test.