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Re: Calculate the included angle between two vectors [message #65972 is a reply to message #65971]

Fri, 10 April 2009 02:15

duxiyu@gmail.com
Messages: 88
Registered: March 2007

Member

Thanks all.

On Apr 10, 1:41 am, Chris <beaum...@ifa.hawaii.edu> wrote:
> On Apr 9, 5:43 am, Pierre <pierre.villene...@gmail.com> wrote:
>
>> On Apr 9, 7:14 am, "dux...@gmail.com" <dux...@gmail.com> wrote:
>
>>> Is there a function which can calculate the included angle between
>>> two three-dimensional vectors?
>
>>> jdu
>
>> Here's a simple solution. Assume v1 and V2 are each three-element
>> vectors of any magnitude. Compute the angle in degrees as follows:
>
>> angle = acos( transpose(v1)#v2 / sqrt(total(v1^2)) / sqrt(total
>> (v2^2)) ) * 180./!pi
>
>> Good luck.
>
> There is an issue with this method due to the fact that acos cannot
> distinguish between positive and negative angles (cos(-theta) = cos
> (theta)).
> I have found this website to be very useful for coding geometry type
> problems like this one:http://local.wasp.uwa.edu.au/~pbourke/geometry/
>
> chris

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[Message index]

		Re: Calculate the included angle between two vectors By: jameskuyper on Fri, 10 April 2009 02:47
		Re: Calculate the included angle between two vectors By: duxiyu@gmail.com on Fri, 10 April 2009 02:15
		Re: Calculate the included angle between two vectors By: Chris[6] on Thu, 09 April 2009 10:41
		Re: Calculate the included angle between two vectors By: Pierre V. on Thu, 09 April 2009 08:43

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