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Vector Quadruple Product


There are a number of algebraic identities involving sets of four vectors. An identity known as Lagrange's identity is given by

 (AxB)·(CxD)=(A·C)(B·D)-(A·D)(B·C)
(1)

(Bronshtein and Semendyayev 2004, p. 185).

Letting A^2=A·A, a number of other useful identities include

(AxB)^2=A^2B^2-(A·B)^2
(2)
Ax(Bx(CxD))=B(A·(CxD))-(A·B)(CxD)
(3)
(AxB)x(CxD)=(CxD)x(BxA)
(4)
=[A,B,D]C-[A,B,C]D
(5)
=[C,D,A]B-[C,D,B]A,
(6)

where [A,B,C] denotes the scalar triple product. Equation (◇) turns out to be relevant in the computation of the point-line distance in three dimensions.


See also

Lagrange's Identity, Scalar Triple Product, Vector Multiplication, Vector Triple Product

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References

Aris, R. Vectors, Tensors, and the Basic Equations of Fluid Mechanics. New York: Dover, pp. 18-20, 1989.Bronshtein, I. N.; Semendyayev, K. A.; Musiol, G.; and Muehlig, H. Handbook of Mathematics, 4th ed. New York: Springer-Verlag, 2004.Griffiths, D. J. Introduction to Electrodynamics. Englewood Cliffs, NJ: Prentice-Hall, p. 13, 1981.Morse, P. M. and Feshbach, H. Methods of Theoretical Physics, Part I. New York: McGraw-Hill, p. 114, 1953.

Referenced on Wolfram|Alpha

Vector Quadruple Product

Cite this as:

Weisstein, Eric W. "Vector Quadruple Product." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/VectorQuadrupleProduct.html

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