Arguments of exponential and trig functions

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The discussion centers on the nature of arguments in exponential and trigonometric functions, questioning whether they can be vectors or must remain scalars. It is noted that while functions expressed as power series can be extended to matrices, the general application to vectors is limited due to the absence of a universal multiplication function yielding vector results. Typically, in physical contexts, arguments are dimensionless, although hypothetical scenarios can create dimensioned arguments. An example involving force and mass illustrates the unusual dimensions that can arise from exponentiating physical quantities. Overall, the consensus suggests that while scalars are standard, there are theoretical allowances for more complex arguments.
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What can be said about the arguments of the exponential functions and trig functions ? Can the argument be a vector or must it be a scalar ? If it can only be a scalar must it be dimensionless ?
 
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dyn said:
What can be said about the arguments of the exponential functions and trig functions ? Can the argument be a vector or must it be a scalar ? If it can only be a scalar must it be dimensionless ?
Any function that can be expressed as a power series can be extended to apply to any algebra - that is, to any ring over a scalar field.
Thus if M is a square matrix then eM can be given a meaning.
This doesn't work for vectors in general because there is no general multiply function with a vector result. (In 3D, you could try to apply it to the cross product, but it becomes rather uninteresting when raising any given vector to a power returns zero.)
If dealing with physical quantities, it will usually be the case that the argument (and result) will be dimensionless. But you could construct artificial situations. E.g. from F=ma you could write eF=ema. Each side has the strange dimension of exponentiated force, and the units could be exponentiated Newtons. Doesn't strike me as useful.
 
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Here is a little puzzle from the book 100 Geometric Games by Pierre Berloquin. The side of a small square is one meter long and the side of a larger square one and a half meters long. One vertex of the large square is at the center of the small square. The side of the large square cuts two sides of the small square into one- third parts and two-thirds parts. What is the area where the squares overlap?

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