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Word/notation for "swallowing constant"?

by HJ Farnsworth
Tags: swallowing constant, word or notation
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HJ Farnsworth
#1
May25-14, 05:50 PM
P: 120
Greetings,

I used to sit in on an astrophysics course, where during derivations the professor would often absorb all of the constants in a given expression into a single ever-changing constant at the front of the expression. E.g., for a trivial example, let [itex]X[/itex] be [itex]3[/itex] times the circumference of a circle of radius [itex]r[/itex] times the perimeter of a square of side length [itex]l[/itex], with [itex]k[/itex] the constant in front:

[itex]X=kC(r)P(l)=krP(l)=krl[/itex].

The constant [itex]3[/itex], the [itex]2\pi[/itex] from [itex]C(r)[/itex], and the [itex]4[/itex] from [itex]P(l)[/itex] are all absorbed into [itex]k[/itex].

Is there a common name for this kind of device, which in the title of this thread I just called a "swallowing constant"? Also, is there a common notation for it?

Thanks for any help that you can give.

-HJ Farnsworth
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HallsofIvy
#2
May25-14, 06:29 PM
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Thanks
PF Gold
P: 39,363
I would use the phrase you did: "absorbed into k". There is no special name for the constant into which other constants because there is nothing special about it.


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