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The linear combination of vectors implies the existence of the cross and dot products. (English) Zbl 1475.97024

Summary: Given two vectors \(\mathbf{u}\) and \(\mathbf{v}\), their cross product \(\mathbf u \times \mathbf v\) is a vector perpendicular to \(\mathbf{u}\) and \(\mathbf{v}\). The motivation for this property, however, is never addressed. Here we show that the existence of the cross and dot products and the perpendicularity property follow from the concept of linear combination, which does not involve products of vectors. For our proof we consider the plane generated by a linear combination of \(\mathbf{u}\) and \(\mathbf{v}\). When looking for the coefficients in the linear combination required to reach a desired point on the plane, the solution involves the existence of a normal vector \(\mathbf{n} = \mathbf{u} \times \mathbf{v}\). Our results have a bearing on the history of vector analysis, as a product similar to the cross product but without the perpendicularity requirement existed at the same time. These competing products originate in the work of two major nineteen-century mathematicians, W. Hamilton, and H. Grassmann. These historical aspects are discussed in some detail here. We also address certain aspects of the teaching of \(\mathbf{u} \times \mathbf{v}\) to undergraduate students, which is known to carry some difficulties. This includes the algebraic and geometric denitions of \(\mathbf{u} \times \mathbf{v}\), the rule for the direction of \(\mathbf{u} \times \mathbf{v}\), and the pseudovectorial nature of \(\mathbf{u} \times \mathbf{v}\).

MSC:

97H60 Linear algebra (educational aspects)
15A99 Basic linear algebra
15-03 History of linear algebra
01A55 History of mathematics in the 19th century
Full Text: DOI

References:

[1] Kustusch M. Student understanding of cross product direction and use of right-hand rules: an exploration of representation and context-dependence [PhD dissertation]. North Carolina State University; 2011. Available from: repository.lib.ncsu.edu/bitstream/handle/1840.16/6895/etd.pdf?sequence=2&isAllowed=y Accessed June 2017.
[2] Arfken G. Mathematical methods for physicists. Orlando (Fl): Academic Press; 1985. · Zbl 0135.42304
[3] Byron F, Fuller R. Mathematics of classical and quantum physics. Mineola (NY): Dover; 1992. · Zbl 1141.00001
[4] Castelvecchi D. Why there’s no such thing as north and south: 2011. Available from: blogs.scientificamerican.com/degrees-of-freedom/no-such-thing-as-north-and-south Accessed June 2017.
[5] Crowe M. A history of vector analysis. Notre Dame (IN): University of Notre Dame Press; 1967. · Zbl 0165.00303
[6] Gibbs J. Elements of vector analysis. Privately printed, New Haven, 1881, 1884. In: The collected papers of J. Willard Gibbs, Longmans, Green, and Co., New York, 1906. p. 17-90.
[7] Hamilton W. On a new species of imaginary quantities connected with a theory of quaternions. Proc Roy Irish Acad. 1844;2:424-434.
[8] Brand L. Vector and tensor analysis. New York (NY): Wiley; 1947. · Zbl 0032.30602
[9] van der Waerden B. Hamilton’s discovery of quaternions. Math Mag. 1976;49:227-234. · Zbl 0348.01007
[10] Hamilton W. Theory of quaternions. Proc Roy Irish Acad. 1847;3:1-16. Available from: books.google.com/books?id=QHbNAAAAMAAJ&printsec=frontcover#v=onepage&q&f=false (accessed June 2017), and umdrive.memphis.edu/jpujol/public/Quaternion/Hamilton-1847.pdf.
[11] Pujol J. On Hamilton’s nearly-forgotten early work on the relation between rotations and quaternions and on the composition of rotations. Amer Math Monthly. 2014;121:515-522. · Zbl 1305.01031
[12] Lass H. Vector and tensor analysis. New York (NY): McGraw-Hill; 1950. · Zbl 0037.23201
[13] Trenkler G. Vector equations and their solutions. Int J Math Education Sci Technol. 1998;29:455-459. · Zbl 1025.15002
[14] Room T. The composition of rotations in euclidean three-space. Amer Math Monthly. 1952;59:688-692. · Zbl 0047.15001 · doi:10.2307/2307548
[15] Hartley R, Zisserman A. Multiple view geometry in computer vision. Cambridge: Cambridge University Press; 2003. · Zbl 0956.68149
[16] Fearnley-Sander D. Hermann Grassmann and the creation of linear algebra. Amer Math Monthly. 1979;86:809-817. · Zbl 0428.01008
[17] Collins J. An elementary exposition of “Grassmann”s Ausdehnungslehre,” or Theory of Extension. Amer Math Monthly. 1899;6:193-198, 261-266, 297-301; 1900;7:31-35, 163-166, 181-187, 207-214, 253-258. · JFM 31.0103.09
[18] Grassmann H. Die lineale Ausdehnungslehre [The linear theory of extension]. Leipzig: Wigand; 1844.
[19] Grassmann H. Die Ausdehnungslehre. Vollständig und in strenger Form bearbeitet. [The theory of extension. Completely and in a more rigorous form rewritten]. Berlin: Enslin; 1862.
[20] Grassmann H. Ueber die Wissenschaft der extensiven Grösse oder die Ausdehnungslehre [On the science of the extensive magnitudes or the theory of extension], Archiv der Mathematik und Physik. 1845;6:337-350. English translation by Beman W, The Analyst. 1881;8:96-97, 114-124.
[21] Grassmann H. Extension theory. Translated by L. Kannenberg. Amer. Math. Soc., Providence, 2000. · Zbl 0953.01025
[22] American Mathematical Society. Available from: http://bookstore.ams.org/hmath-19/ Accessed Nov 2017.
[23] Grassmann H. Geometrische Analyse [Geometrical analysis]. Leipzig: Weidmann’sche Buchhandlung; 1847.
[24] Vince J. Geometric algebra for computer graphics. London: Springer; 2008. · Zbl 1155.68084 · doi:10.1007/978-1-84628-997-2
[25] Noble B, Daniel J. Applied linear algebra. Englewood Cliffs: Prentice-Hall; 1977. · Zbl 0413.15002
[26] Brand L. Vector analysis. New York (NY): Wiley; 1957. · Zbl 0077.14902
[27] Crapper E. Vectors and graphs and their practical applications. Technics. 1904;1:224-226.
[28] Hestenes D. Grassmann’s vision. In: Schubring G, editor. Hermann Günther Grassmann (1809-1877): visionary mathematician, scientist and neohumanist scholar. Dordrecht: Springer; 1996. p. 243-254. Available from: http://geocalc.clas.asu.edu/ pdf/GrassmannsVision.pdf. Accessed June 2017. · Zbl 0907.01012 · doi:10.1007/978-94-015-8753-2_20
[29] Grassmann H. Der Ort der Hamilton’schen Quaternionen in der Ausdehnungslehre [The place of Hamilton’s quaternions in the theory of extension]. Mathematische Annalen. 1877;12:375-386. · JFM 09.0512.01
[30] Reich K. The emergence of vector calculus in physics: the early decades. In: Schubring G, editor. Hermann Günther Grassmann (1809-1877): visionary mathematician, scientist and neohumanist scholar. Dordrecht: Springer; 1996. p. 197-208. · Zbl 0907.01021 · doi:10.1007/978-94-015-8753-2_16
[31] Reich K. Rudolf Mehmke, an outstanding propagator of Grassmann’s vector calculus. In: Petsche H-J, Lewis A, Liesen J, Russ S, editors. From past to future: Graßmann’s work in context. Basel; Springer; 2011. p. 209-220. · Zbl 1216.01012 · doi:10.1007/978-3-0346-0405-5_19
[32] Kuipers J. Quaternions and rotation sequences: a primer with applications to orbits, aerospace and virtual reality. Princeton: Princeton University Press; 2002. · Zbl 1053.70001
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