Prove: u × (v + w) = (u × v) + (u × w)

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SUMMARY

The discussion centers on proving the vector identity u × (v + w) = (u × v) + (u × w) using established vector properties. Participants reference the anti-commutative property v × u = −(u × v) and the distributive property (u + v) × w = (u × w) + (v × w) as foundational tools for the proof. The initial step involves applying the anti-commutative property to rewrite u × (v + w) as -(v + w) × u, which leads to the conclusion that the identity holds true for all vectors u, v, and w.

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  • Familiarity with anti-commutative property of vectors
  • Knowledge of distributive property in vector addition
  • Basic proficiency in vector algebra
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mk_29
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For all u, v,w, we have v × u = −(u × v) and (u + v) × w = (u × w) + (v × w).

Apply these facts to prove, without using co-ordinates, that for all vectors u, v,w, we have

u × (v + w) = (u × v) + (u × w).

I need help, do not know were to start.

Thaks
 
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Start with ux(v+w)=-(v+w)xu. Do you see why you can do that? It's your first property.
 
Dick said:
Start with ux(v+w)=-(v+w)xu. Do you see why you can do that? It's your first property.

Oh, ok i see what you have done. Know it should easy for me 2 prove this.

Thanks for the help
 

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