How to Draw a Graph of a Quadratic Function:

By: Dian Sulistiani / 2010110027

Before Revision:

How to draw a graph of a quadratic function:

Ø  Choose the quadratic function

Ø  See the function and determine the function is face up wards or face down wards.

Ø  Determine intersection point at x-axis. We can solve it with the step: substitute y = 0 into the function so we get x₁ and x₂ or we can use the factorization methods to solve the problem.

Ø  Determine the minimum or maximum point. We can use the steps: determine the axis of symmetry of x and substitute x into function. So we can get the y- value.

Ø  Determine the other points {x, y}

Ø  Plot the point {x, y} that you have found into Cartesian diagram.

Ø  Connect each point so we get the parabolic graph.

Ø  Or we can solve it by Geogebra software, please open the Geogebra software.

Ø  Input the function on input box and push the enter button.

Ø  We get the graph.

After Revision:

How to draw a quadratic function:

Ø  Choose the quadratic function. The general form of a quadratic is “y = ax² + bx + c”.

Ø  Determine the intersection point to x-axis if y = 0.

Ø  Determine the intersection point to y-axis if x = 0.

Ø  Determine the symmetry of x-axis. We can use the formula x = -b/2a

Ø  Determine culminating point ( -b/2a, (b² - 4ac)/4a), if a > 0 so, the function has minimum point and if a < 0, the function has maximum point.

Ø  Determine some of helping points. We can substitute x-value else into y so we get some other point (x, y)

Ø  Plot the point (x, y) that you have found into Cartesian diagram.

Ø  Connect each point so we get the parabolic graph.

Ø  Or we can solve it by Geogebra software, please open the Geogebra software.

Ø  Input the function on input box and push the enter button.

Ø  We get the graph.