Presentation on theme: "WHAT IS AN ELLIPSE? Definition Equation Graph What is an ellipse? An ellipse is a conic section formed by the intersection of a plane and a cone. Click."— Presentation transcript:
WHAT IS AN ELLIPSE? Definition Equation Graph
What is an ellipse? An ellipse is a conic section formed by the intersection of a plane and a cone. Click hereClick here to see an applet that will allow you to display and animate the intersection of a plane and the surface of a cone.
DEFINITION An ellipse is the set of all points in the plane such that the sum of the distances from two fixed points (called foci) is constant. Note that this is clearly a geometrical definition and does not point out the relationship between an ellipse and its algebraic equation.
EQUATION An ellipse with center at (x 0,y 0 ) can be defined algebraically in standard form by the equation: It is important to remember: a is the distance from the center to the end of major axis b is the distance from the center to the end of major axis c is the distance from the center to the focus a 2 = b 2 + c 2
GRAPHS Click here to see how the equation for an ellipse relates to its graph. Click here When graphing an ellipse it is useful to remember these facts: center is (x 0,y 0 ) length of the major axis is 2a length of the minor axis is 2b distance between foci is 2a
PRACTICE Lets try some practice problems and see what you have learned.practice problems Click here Click here for more practice problems. Try these problems for more practice.more practice
WHY WOULD I WANT TO KNOW ABOUT ELLIPSES? Whispering Galleries Planetary Orbits Haleys Comet Lunar & Solar Eclipses Elliptical Galaxies