Uploaded October 2022 | Updated September 2026, 1 week ago

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In this video, I derived the half angle formulas for sin and cos.

cos(a+b) PROOF: youtu.be/UtNyHeWBqCk
Pythagorean trig identity PROOF (Near the end of the video): youtu.be/FLuG9MnrKjE

#trigonometry #maths #math #science #equation