a.b= a(x) * b(x) + a(y) * b(y) + a(z) * b(z)(adsbygoogle = window.adsbygoogle || []).push({});

and this is equal to a*b*cosm

where a and b is the magnitude of the vectors in space and m is the angle between them.

I really wonder why this equation is true. I couldn't find the proof anywhere and the teacher didn't show it, he only wrote the formula.

I am a really fanatic of proving such theorems; if you can advise me a book that might catch my interest, I'd be glad.

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# There is a formula such as

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