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"Show" that the direction cosines of a vector satisfies

$$\cos^2 \alpha + \cos^2 \beta + \cos^2 \gamma = 1$$

I am stumped on these things:

  1. "SHOW" that the direction cosines corresponds to a given vector to satisfy the relation above. ----> How do you "show" this? What does this mean? Does this mean to use the direction cosines of a vector?
    1. I'm sure this is a proof but I don't know what the end result would look like or better, what I am expected to learn from this proof.

I am not looking for a mere answer but really an in-depth explanation of the problem.

Greatly appreciated. :)

  • 2
    "Show" means exactly the same as "prove". Some authors use it in exercises in an attempt to sound less scary; others alternate between "show" and "prove" simply for linguistic variation.2012-09-02

3 Answers 3