The equation of a a quadratic function can be determined from a graph showing the y-intecept, axis of symmetry and turn point.

Part of

In this part you do not have to sketch the graph and you may even be given the sketch of the graph to start with.

For a quadratic equation of the form , the following diagram shows the main properties:

If k > 0, the vertex is a minimum turning point

If k < 0, the vertex is a maximum turning point

We can identify these properties from a quadratics graph or equation.