Trig Proof 1

Trig Proof 1
  • Currently 4.0/5 Stars.
2918 views, 2 ratings - 00:09:12
Part of video series Trig Proofs
Taught by YourMathGal
More free YouTube videos by Julie Harland are organized at
At 12 seconds into the video, cot(theta) is listed as cos(theta) / tan(theta), but it should say cot(theta) = cos(theta)/sin(theta).
Shows steps for proving (or verifying) Trigonometric Identities;
  • How do you verify / prove trig identities?
  • How do you prove that (cos(x)*sin^2(x) + cos^3(x))/sin(x) = cot(x)?
  • How do you prove that sin^2(x)/cos(x) = sec(x) - cos(x)?
  • How do you prove that tan(theta)*cos(theta) + csc(theta)*sin^2(theta) = 2*sin(theta)?
  • What are some fundamental trig identities that you need to know to prove trig formulas?
  • What are the Pythagorean identities for trigonometry?
This lesson shows how to verify / prove trig identities / formulas. Some tricks / techniques for transforming the left side of the trig identities to make them look like the right side are shown and explained. If you struggle with proving trig identities, this is a great lesson to watch.
  • Currently 4.0/5 Stars.
Reviewed by MathVids Staff on November 10, 2010.
Theres a small error in the fundamental identities at the beginning f the video. cotx is listed as cosx/tanx. Should be cosx/sinx. Excellent teacher though... Soothing voice and perfect pace I love that she uses color so effectively. Hopefully she adds more (conics?, trig transformstions?)
  • Currently 4.0/5 Stars.
Reviewed by darkhydrastar on January 16, 2011.
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