Lesson 1 - Drawing a parabola
Parabolas are among the most appealing and useful curves. Back to the ancient times it was known by the Greeks that a parabola could be constructed as a conic section. Also there are many reasons for looking at this curve in physics. If you rotate a parabola around its axis you will get a paraboloid, and this shape is used in the design of radio telescopes and satellite dishes. The reason for this is simple: the parabola reflects ray parallel to its axis so that all the rays meet in one point called the focal point.
When you throw a ball at an angle to ground, it will follow a path that is a parabola.
Drawing a parabola with the Function Plotter
A formula for a parabola is the following:
y = a x2
To create a parabola in CorelDRAW follow these steps:
- Click on the Function Plotter button on the tool bar in CorelDRAW.
- Specify the following parameters in the Plotter dialog fields:
x(t): t
y(t): 0.5*t^2
T From: -4
T To: 4
Leave the field T Step at its default value (To-From)/100 which will give you 100 points in the function plot. The more nodes you select, the smoother the curve gets. That could be important if you draw a complex curve, however for a simple parabola, 100 points are enough. -
Let's change the background color to blue and the curve color to black:
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Click the Chart Area tab to change the сhart settings.
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Click the Fill button under Chart Area Properties and choose a blue-green color - RGB(100,200,200).
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Under Plot Area Properties change the Fill color to a light blue color - RGB(0,120,190), and the Border color to a dark blue color - RGB(200,220,220) and 2 point width, as shown on the picture below:
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- Click the Data tab and click the Line button under Plot Properties and set the line color to Black and width to 2 points.
- Now click the Generate! button. The parabola drawing will be
created in CorelDRAW. You can close the dialog to see the result:
