Question 6 - Ellipses & Parabolas
Key Concepts
How to Draw an Ellipse - Circle Method
1 - Draw a circle with a diameter equal to the major axis and a circle with a diameter equal to the minor axis using the same centre
2 - Divide the circles into 12 slices using your 30 deg set square 3 - Draw a vertical line down from each point where the lines meet the outer circle and draw a horizontal line across where the lines meet the smaller circle. Mark out the points where the horizontal and vertical lines meet. 4 - Use these points to freehand sketch the ellipse
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How to Draw a Tangent to an Ellipse at a Point, p1 - Locate the 2 focal points, F1 & F2
2 - Draw a line from each focal point to P and extend them outside the ellipse 3 - Bisect the angle between the focal point lines as shown in blue
4 - The tangent is the line that bisects the angle at P
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Finding the minor axis given a point on the ellipse |
Parabola
How to Draw a Parabola (Rectangle Method)
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Past Exam Questions
Simpler ellipse questions also appear in Section A
Useful Tips
Useful Tips
- Know how to find the minor axis given the major axis and a point on the ellipse (p244 in the Textbook)
- You can use axial symmetry to draw the second half of an ellipse or parabola
- If you can't figure out how to find a certain point, guess it and keep going with the rest of the construction. You'll only be penalised once.