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Exam question t/f

  • Thread starter Mdhiggenz
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  • #1
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Homework Statement



So I took my calc 3 exam today and had this question

true or false

magnitude ( v+v) = 2*magnitude( v)

I put true.

Thoughts?


Homework Equations





The Attempt at a Solution

 

Answers and Replies

  • #2
LCKurtz
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You got it correct. Were you just guessing?
 
  • #3
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No I did a problem where I had to solve for K in the magnitude give the value of v. Pretty much I took k from the magnitude and solved for it. So I was hoping the same thing applied here.
 
  • #4
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You got it correct.
Really? I don't see how this is correct.
 
  • #5
LCKurtz
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Really? I don't see how this is correct.
If ##\vec v = \langle a,b,c\rangle## what do you get for ##|\vec v|## and ##|2\vec v|##?
 
  • #6
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If ##\vec v = \langle a,b,c\rangle## what do you get for ##|\vec v|## and ##|2\vec v|##?
Sorry, of course it's correct.

I was having a senile moment when I was imagining the two vectors weren't the same! D'oh! :redface:
 
  • #7
LCKurtz
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Sorry, of course it's correct.

I was having a senile moment when I was imagining the two vectors weren't the same! D'oh! :redface:
Don't feel to bad about that. My first reaction was the same because I was expecting the question to read u+v since, in my opinion, that would have been a better question. Only after I started my reply did I realize the OP had v+v.
 
  • #8
vela
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Sorry, of course it's correct.

I was having a senile moment when I was imagining the two vectors weren't the same! D'oh! :redface:
Did the same thing here. :smile:
 
  • #9
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Don't feel to bad about that. My first reaction was the same because I was expecting the question to read u+v since, in my opinion, that would have been a better question. Only after I started my reply did I realize the OP had v+v.
Did the same thing here. :smile:
I obviously need to learn to read twice before posting. Something which you two are obviously better at than me! :smile:
 
  • #10
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If v happened to be perpendicular to itself, the original statement wouldn't be true.:tongue:

(The zero vector not included, of course.)
 
  • #11
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If v happened to be perpendicular to itself, the original statement wouldn't be true.:tongue:

(The zero vector not included, of course.)
Now you've lost me!
 
  • #12
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Math humor...

A nonzero vector can't be perpendicular to itself.
 
  • #13
LCKurtz
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Math humor...

A nonzero vector can't be perpendicular to itself.
What if it's bent?
 

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