Trig Proof 8

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Taught by YourMathGal
  • Currently 4.0/5 Stars.
1207 views | 1 rating
Part of video series
Meets NCTM Standards:
Lesson Summary:

In this lesson, Math Gal demonstrates how to verify a tricky trig identity using basic identities and the identity for the cosine of a sum or difference. By manipulating the left-hand side of the equation using these methods, Math Gal is able to transform it into the right-hand side of the equation, ultimately proving that (cos(A + B))/(sin(A - B)) = (1 - tanA * tanB)/(tanA - tanB). This lesson is a great resource for anyone struggling with trig identities and looking to improve their problem solving skills in this area.

Lesson Description:

We verify a Trig identity by using the basic identities and the identity for the cosine of a sum or difference. We prove that (cos(A + B))/(sin(A - B)) = (1 - tanA * tanB)/(tanA - tanB) using a trig proof.

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

Questions answered by this video:
  • How do you do a trig proof?
  • How do you prove that (cos(A + B))/(sin(A - B)) = (1 - tanA * tanB)/(tanA - tanB)?
  • Staff Review

    • Currently 4.0/5 Stars.
    This is another good tutorial on how to manipulate one side of a trig equation to prove that it equals the other side. All steps involved in the proof are shown and explained.