Derive Trig Half Angle Identities

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Taught by YourMathGal
  • Currently 4.0/5 Stars.
1638 views | 1 rating
Part of video series
Meets NCTM Standards:
Lesson Description:

Video derives the half angle trigonometry identities for cosine, sine and tangent

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

Questions answered by this video:
  • What are the trig half angle identities?
  • How can you derive the trig half angle identities?
  • How can you use the trig double angle identities to derive the half angle identities?
  • What is the formula for cos(x/2) and how to you derive it?
  • What is the formula for sin(x/2) and how to you derive it?
  • What is the formula for tan(x/2) and how to you derive it?
  • Why are there multiple formulas for the tan(x/2) and how do you derive them?
  • How do you derive the formula tan(x/2) = (sinx)/(1 + cosx)?
  • How do you derive the formula tan(x/2) = (1 - cosx)/sinx?
  • Staff Review

    • Currently 4.0/5 Stars.
    This lesson is very similar to the previous lesson in this series, but instead of deriving double angle identities, you will learn how to derive the half angle trig identities. Each step in the derivation process is explained.