ALEX Classroom Resource


Finding the Foci of an Ellipse From an Equation

  Classroom Resource Information  


Finding the Foci of an Ellipse From an Equation


Content Source:

Khan Academy
Type: Learning Activity


In this instructional video and practice activity from Khan Academy, students will explore how the radii and the foci of an ellipse relate to each other and how this relationship can be used to find the foci from the equation of an ellipse. This video can be used during a lesson on solving systems of equations. The video is 13 minutes and 48 seconds in length and can be assigned through Google Classroom. There are practice problems included after the video.

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Content Standard(s):
MA2015 (2016)
Grade: 9-12
37 ) (+) Derive the equations of ellipses and hyperbolas given the foci, using the fact that the sum or difference of distances from the foci is constant. [G-GPE3]

Tags: ellipse, equations, foci, radii
License Type: Custom Permission Type
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Partnered Event: ALEX Resource Development Summit
AccessibilityVideo resources: includes closed captioning or subtitles

2019 ALCOS


37. Use trigonometric identities to solve problems.

a. Use the Pythagorean identity sin^2 (θ) + cos^2(θ) = 1 to derive the other forms of the identity.
Example: 1 + cot^2 (θ) = csc^2 (θ)

b. Use the angle sum formulas for sine, cosine, and tangent to derive the double angle formulas.

c. Use the Pythagorean and double angle identities to prove other simple identities.

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The event this resource created for:ALEX Resource Development Summit