How many people were taught that the formulas for the dot product (x₁x₂ + y₁y₂ + z₁z₂) and cross product (y₁z₂ − y₂z₁, z₁x₂ − z₂x₁, x₁y₂ − x₂y₁) are simply definitions and cannot be derived?

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• URL: https://x.com/EricLengyel/status/1229229674397437954
• Author: Eric Lengyel (@EricLengyel)
• Posted: 2020-02-17 02:22:47

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1/ @EricLengyel

How many people were taught that the formulas for the dot product (x₁x₂ + y₁y₂ + z₁z₂) and cross product (y₁z₂ − y₂z₁, z₁x₂ − z₂x₁, x₁y₂ − x₂y₁) are simply definitions and cannot be derived?

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