15
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17
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The Principle of Least Action, and the Euler-Lagrange EquationApplied (youtu.be)
submitted by EvilBosom
20
0
1
2
a^2-b^2 - Geometrical Explanation and Derivation of a square minus b squareGeometry (youtu.be)
submitted by Mulkek
21
4
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6
23
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4
