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## #1 Re: Help Me ! » Vector Cross and Dot Product » 2006-03-22 11:19:47

eh... if anyone is interested in the solution, here it is:

It's really simple actually... Because it is a CIRCLE, 2-dimensional shape, the scalar triple products are all equal to zero...
Three vectors in a 2D plane are always linearly dependent.

## #2 Re: Help Me ! » Vector Cross and Dot Product » 2006-03-18 04:59:54

Yes I know how to prove it algebraically... just not with the diagram.

## #3 Help Me ! » Vector Cross and Dot Product » 2006-03-17 17:09:25

NoSash
Replies: 5

See the image, show using the diagram...
I have no idea how to apply the diagram.

## #4 Re: Help Me ! » Four Equals Five » 2006-02-13 11:52:50

Hey guys, apparently it's incorrect to put the absolute value signs, can anybody confirm this? Or support it? I know it works out mathematically but I was told it's still wrong.

## #5 Help Me ! » Prove Associative Law using Vectors » 2006-02-09 10:53:22

NoSash
Replies: 1

How can I prove the associative law (multiplication) using vectors:
m(na) = (mn)a    where m and n are real numbers, and a is a vector?

There are three cases to prove:
m>0, n>0
m<0, n<0
m>0, n<0 and m<0, n>0

I have no idea where to start.

## #6 Re: Help Me ! » Four Equals Five » 2006-02-07 04:51:39

yeah it all makes sense, thanks guys

## #7 Help Me ! » Four Equals Five » 2006-02-06 10:48:11

NoSash
Replies: 7

1)                           16 - 36 = 25 - 45
2)                16 - 36 + 81/4 = 25 - 45 + 81/4
3) 4^2 - 2x4x9/2 + (9/2)^2 = 5^2 - 2x5x9/2 + (9/2)^2
4)                     (4 - 9/2)^2 = (5 - 9/2)^2
5)                           4 - 9/2 = 5 - 9/2
6)                                   4 = 5

What went wrong?

I'm pretty sure the error is from step 3 to 4 but I don't know what the heck they are trying to do.