Recall:
HOW TO GRAPH A QUADRATIC FUNCTION:
1) Locate the vertex (see previous tutorial).
2) I highly recommend learning a shortcut for graphing other points (see “From the Vertex” and “Point-to-Point” tutorials).
3) If you have trouble learning and/or remembering a shortcut, you will have to use the function to find more points – I recommend finding three points on each side of the vertex.
· Use a table of values to organize your points.
· Write the vertex in the middle of this table.
· Choose x-coordinates (I recommend three of them) on each side of the vertex and write these in the table.
· For each x-coordinate, you will need to substitute it into the function in order to find the corresponding y-coordinate.
· When you are finished, plot the points from your table and draw the parabola.
o REMEMBER – both sides of the parabola should be mirror images of each other… if this is not the case with your parabola, you’ve done something wrong.
o If you are asked to show the axis of symmetry, it is an imaginary (dashed) vertical line that passes through the vertex of the parabola.
EXAMPLES WITH EXPLANATIONS: (Click on images to enlarge)