Trig Double Angle Formula

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Taught by YourMathGal
  • Currently 4.0/5 Stars.
2036 views | 1 rating
Part of video series
Meets NCTM Standards:
Lesson Description:

Video derives the double angle trigonometry formula and provides examples using the formula.

More free YouTube videos by Julie Harland are organized at http://yourmathgal.com

Questions answered by this video:
  • What are the trig double angle formulas?
  • What are the double angle identities for sine, cosine, and tangent?
  • How do you derive the double angle identities for sine, cosine, and tangent?
  • How do you derive cos(2A)?
  • How do you derive sin(2A)?
  • How do you derive tan(2A)?
  • Why are there different double angle formulas and how do you derive them?
  • Why can cos(2A) equal cos^2(A) - sin^2(A), 1 - 2sin^2(A), or 2cos^2(A) - 1?
  • Staff Review

    • Currently 4.0/5 Stars.
    This lesson will show you how to derive the formulas for sin(2A), cos(2A), and tan(2A) using the formulas that you should already know from the previous lessons in this series. All steps involved in the derivation of these double angle formulas are shown and explained.