Vertex Form
Vertex Form
Graph a Parabola
Example
Graph the function: y = (x - 2)2 - 1.
Step 1. Find the vertex and axis of symmetry.
For this equation, the vertex is (2, -1) and the axis of symmetry is x = 2.
Step 2 . Find the y-intercept.
y = (0 - 2)2 - 1
y = (-2)2 -1
y = 4 - 1
y = 3
The y-intercept is (0, 3).
Step 3. Use the y-intercept and axis of symmetry to find another point.
Since (0, 3) is 2 units away from x = 2, the corresponding point is 2 units on the other side of the axis, therefore a point on the graph is (4, 3).
Step 4. Plot the points determined and sketch the curve.