Product of 2 vectors help

  • #1
gtfitzpatrick
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Homework Statement



r.k where r=xi+yj+zk



The Attempt at a Solution



is the answer to this just z or is it x+y
 

Answers and Replies

  • #2
cristo
Staff Emeritus
Science Advisor
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Well, why do you think it is either of the answers you quote?

What is the definition of the dot product of two vectors?
 
  • #3
gtfitzpatrick
380
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Dot product of 2 vectors a.b is a1b1+a2b2+a3c3?
 
  • #4
gtfitzpatrick
380
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i think k.k = 0
 
  • #5
cristo
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Science Advisor
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Dot product of 2 vectors a.b is a1b1+a2b2+a3c3?
Ok, good. So, presumably, this definition is for two vectors a=(a1,a2,a3) and b=(b1,b2,b3). Can you write your two vectors in this form?

i think k.k = 0
Hold on.. this doesn't agree with what you stated above. Have another think...
 
  • #6
gtfitzpatrick
380
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xi+yj+zk.k so this is x0+y0+z1 = z?
 
  • #7
cristo
Staff Emeritus
Science Advisor
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Yup, that's correct.
 
  • #8
gtfitzpatrick
380
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thanks a mill
 
  • #9
cristo
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Science Advisor
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No problem!
 

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