The dot product [3 1 4]dot 2

-1

5 is.

My answer is 25, but I'm not sure. Thanks for any help given.

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- Jul 20th 2006, 07:24 AMkwtolleyDOT Product
The dot product [3 1 4]dot 2

-1

5 is.

My answer is 25, but I'm not sure. Thanks for any help given. - Jul 20th 2006, 09:09 AMCaptainBlackQuote:

Originally Posted by**kwtolley**

$\displaystyle

\bold{x}\cdot \bold{y}=\sum_{i=1}^3 x_i y_i = x_1y_1+x_2y_2+x_3y_3

$.

In this case we have $\displaystyle \bold{x}=[3,1,4]$ and $\displaystyle \bold{y}=[2,-1,5]$, so:

$\displaystyle

\bold{x}\cdot \bold{y}= 3\times 2+1\times (-5)+4\times 5=21

$.

RonL - Jul 20th 2006, 09:19 AMkwtolleythank you
I really needed help on that one. I was way off on seting it up. thanks again for checking

- Jul 20th 2006, 11:43 AMtopsquarkQuote:

Originally Posted by**CaptainBlack**

The last line should read:

$\displaystyle \bold{x}\cdot \bold{y}= 3\times 2+1\times (-1)+4\times 5=25

$.

So you were correct, ktwolley.

-Dan - Jul 20th 2006, 12:21 PMCaptainBlackQuote:

Originally Posted by**topsquark**

Hopefully they provide enough information that they have in fact done

what they say they are doing :o

RonL - Jul 20th 2006, 07:59 PMkwtolleyIts alllllll good
Thanks both of you. I check and recheck myself and other, but sometimes the problems are hard. Thanks again you guys here are a big help.