Classic math proofs of the law of sine and the law of cosine
10:37
Heron's Formula Proof (the area of a triangle when you know all three sides)
33:16
exact value of sin(3 degrees)
13:57
Pythagoras Would Be Proud: High School Students' New Proof of the Pythagorean Theorem [TRIGONOMETRY]
16:29
Trigonometry - Easy to understand 3D animation
21:45
Why You Can't Bring Checkerboards to Math Exams
14:35
the famous Calculus proof of the Pythagorean theorem.
14:33
a RARE mistake from Euler (AIME 1989)
9:37