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Dr. Math FAQ
- About Ellipses,
a selection of answers from the Dr. Math archives.
- Ellipse & Parabola Formulas - Dr. Math FAQ
- A conic (or conic section) is a plane curve that can be obtained by
intersecting a cone with a plane that does not go through the vertex of
the cone... If no line of the cone is parallel to the plane,
the intersection is a closed curve, called an ellipse.
- Uses of Ellipses
- Where are ellipses found in real life?
- Difference between Oval
- What is the difference between an oval and an ellipse? Am I right
if I say that "all ellipses are ovals, but all ovals cannot be ellipses"?
- Perimeter of an Oval
- What is the perimeter of an oval called?
- Drawing an Ellipse
- Drawing An Ellipse
- How do you draw an ellipse with only a straight edge and a compass?
- Accurate Drawing of an Ellipse
- Draw an ellipse accurately using simple tools.
- Tracing an Ellipse
- How do you form an ellipse using 3 points?
- Ellipse Area and Circumference
- How can I draw an ellipse and find the area and circumference?
- Area of an Oval
- How do I figure out the area of an oval 17" x 38"?
- Area of an Ellipse using Integral Calculus
- How do you find the area of an ellipse?
- Area of an Ellipse without using Calculus
- How do you find the area of an oval without using calculus?
- Area of Part of an Ellipse
- Given an ellipse with a line bisecting it perpendicular to either the major
or minor axis of the ellipse, what is the formula for the area of the ellipse
either above or below that line?
- Area of an Ellipse Cut by a Chord
- How can you calculate area of the part of an ellipse cut off by a chord,
if you know the major and minor axes, and the chord?
- Area of A Sector of An Ellipse
- Finding the area of a sector of an ellipse, given the semiminor and major
axes and the angles of the 2 vectors bounding the sector.
- Circumference of an Ellipse
- Is there a formula for determining the circumference or distance around
- Formula for the Circumference of
- What is the formula for the circumference of an ellipse?
- The Perimeter of an Ellipse or Oval
- What is the formula for calculating the perimeter of an oval, or an ellipse?
- Perimeter of an Ellipse
- Is there a formula that gives the exact perimeter of an ellipse?
- Equations, Graphing...
- Foci of an Ellipse
- If the major and minor axis of an ellipse are given, how do I find the
- Graphing an Ellipse
- How do you graph an ellipse? What is the equation?
- Definition of an Ellipse
- The equation for an ellipse is Pf + Pr= 2a where P is a point on the ellipse
and f and r are the points of the foci. How do we know that this is true,
that Pf + Pr = 2a? How did we come up with the constant of 2a?
- Distance from Point to Ellipse
- How do you find the minimum distance from a point to an ellipse when
the point can be either inside or outside the ellipse?
- Ellipse Equation
- How do I get the equation of an ellipse, given four points and the
inclination of the major axis?
- Point on an Ellipse
- Given an ellipse and an arbitrary angle theta from either axis, how do
you find the coordinates of the intersection of the ellipse and a vector
formed by angle theta?
- Points within an Ellipse
- How to generate points that will be within an ellipse.
- Folding a Circle to Get an Ellipse
- How can I prove that taking a point on a circle, folding it to an interior
point, and repeating this process creates an envelope of folds that forms an
- Ellipse Geometry
- I wish to draw a line departing at a given angle from the long axis
of an ellipse and bisecting the perimeter of the ellipse at right angles
to the tangent at that point...
- Tangent Common to Two Ellipses
- I have two general ellipses in space and I want to find the equation
of the tangent common to these ellipses.
- Slope of Tangent to an Ellipse
- If I know a point on an ellipse, how do I find the angle of the
ellipse at that point?
- Finding the Axes of an Ellipse
from a Known Cone
- I'm trying to solve a specific situation regarding lighting when
viewed as an oblique circular cone...
High School Conic Sections/Circles
Index of Selected Answers to Common Questions
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