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Quick question regarding vectorsby sandy.bridge
Tags: vectors 
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#1
Feb613, 05:48 PM

P: 778

If I have a vector defining numerous quantities of the same units, can I merely place the units outside of the vector, or is it required to have units on every entity within the vector?
For example, [tex](A, B, C)=(ae^{j\phi_1}, be^{j\phi_2}, ce^{j\phi_3}) H[/tex] or [tex](A, B, C)=(ae^{j\phi_1} H, be^{j\phi_2} H, ce^{j\phi_3} H)[/tex] 


#2
Feb613, 05:53 PM

P: 2,805

My two cents is for clarity place the units of measure inside. Its not a factor.
For example, a position vector r=<1.0m,2.0m,3.0m> is much clearer than <1.0,2.0,3.0> m as someone might think its some undefined constant. 


#3
Feb613, 05:57 PM

P: 778

Perfect. Since we are on the topic: in regards to notation, is there a difference between using (, [, or <?



#4
Feb613, 06:21 PM

P: 2,805

Quick question regarding vectors
But I did find this: http://en.wikipedia.org/wiki/List_of...atical_symbols which may answer your questions. 


#5
Feb613, 06:34 PM

P: 194

You can place the unit outside of the delimiter  see, for example, http://physics.nist.gov/Pubs/SP811/sec07.html section 7.7 (I believe the SP811 follows the ISO 31000 series in this respect)



#6
Feb613, 09:20 PM

P: 2,805




#7
Feb713, 01:15 PM

P: 194

3rd edition http://www.bipm.org/utils/common/doc...M_200_2012.pdf 1 Quantities and units 1.1 (1.1) quantity property of a phenomenon, body, or substance, where the property has a magnitude that can be expressed as a number and a reference NOTE 5 A quantity as defined here is a scalar. However, a vector or a tensor, the components of which are quantities, is also considered to be a quantity. 1.19 (1.18) quantity value value of a quantity value number and reference together expressing magnitude of a quantity NOTE 4 In the case of vector or tensor quantities, each component has a quantity value. EXAMPLE Force acting on a given particle, e.g. in Cartesian components (Fx; Fy; Fz) = (31.5; 43.2; 17.0) N. ... if it's good enough for the BIPM and ISO, it's good enough for me. 


#8
Feb713, 02:55 PM

P: 2,805

Also they suggest using ; instead of , 


#9
Feb713, 03:07 PM

Math
Emeritus
Sci Advisor
Thanks
PF Gold
P: 39,345




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