Quadratic Functions Graph Plotter

This is a program that can plot graphs for quadratic functions. The general format of a quadratic equation is f(x)= ax²+bx+c , where a, b and c are constant.

This program  employs a picture box as the plot area and three text boxes to obtain the values of the coefficients a, b, c of the quadratic equation from the users. We also need to modify the scale factor in the properties windows of the picture box. I am using a scale of 0.5 cm to represent 1 unit .
Besides, we need to make some transformation as the coordinates in VB start from top left but I want it to start from the middle. I am using the Pset method to draw the graph using a very small increment.

This program is useful for high school students and mathematics teachers.

The Code

Private Sub cmd_draw_Click()
Dim a, b, c As Integer
Dim w, v As Single
a = Val(txt_a.Text)
b = Val(txt_b.Text)
c = Val(txt_c.Text)

'Using a scale of 0.5 cm to represent i unit to draw the graph
' Need to make some transformation as the coordinates in VB start from top left
For w = 0 To 10 Step 0.001

v = a * (5 - w) ^ 2 - b * (5 - w) + c
pic_graph.PSet (w, 5 - v)

Next w

End Sub


Private Sub Command1_Click()
pic_graph.Cls

txt_a.Text = ""
txt_b.Text = ""
txt_c.Text = ""

End Sub