Product of 2 vectors help

  • #1

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
8,107
73
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
Dot product of 2 vectors a.b is a1b1+a2b2+a3c3?
 
  • #5
cristo
Staff Emeritus
Science Advisor
8,107
73
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
xi+yj+zk.k so this is x0+y0+z1 = z?
 
  • #7
cristo
Staff Emeritus
Science Advisor
8,107
73
Yup, that's correct.
 
  • #9
cristo
Staff Emeritus
Science Advisor
8,107
73
No problem!
 
Top