GeoGebra Classroom

A quadratic function is in GENERAL FORM if it is written as f(x)=ax2+bx+c below is a function written in general form, with sliders for the a, b and c values. By the end of this tutorial, you should understand: how the a value affects the shape of the parabola how the c value affects the shape of the parabola
Before you start, set your sliders so that the function is written as Note: the on the end isn't needed, it's just

## Investigating the "a" value

Click and drag the "a" value to the right. How does the parabola look when "a" equals 2? or 3? or 4 or 5? What does increasing the value of "a" do?

Drag the "a" value between 0 and 1. What does decreasing the "a" value, while keeping it positive, do to our parabola?

Drag the "a" value so that it is negative. How does this effect the shape of our parabola?

## Investigating the c value.

Set your function to again. Let's start from here and figure out what the c value does.

Try increasing the c value. What happens? Try decreasing the c value. What happens? Describe what you see

Now move the "a" value and the "b" value to different positions. Now move the "c" value? What particular point on the parabola does the "c" value always coincide with?