Proper math equation 5 variables equal same function

Proper math equation 5 variables equal same function

Postby Guest » Wed Aug 08, 2018 10:00 am

Hi all,

I have a fairly simple question but I could not find in on the internet.
What is the proper way to express in a mathematical formula: q, w, e, 1 over r and minus t equal something?

I was thinking this:

q, w, e, [tex]\frac{1}{r}[/tex], -t = 10log(4\piR^{2})

Kind regards
Guest
 

Re: Proper math equation 5 variables equal same function

Postby Guest » Thu Aug 09, 2018 6:49 am

Maybe it would be
[tex]q+w+e+\frac1r-t=10log...[/tex]
Guest
 

Re: Proper math equation 5 variables equal same function

Postby HallsofIvy » Wed Mar 06, 2019 10:19 am

No, you can't have commas in a "proper equation" like this. Listing variables with commas says you are going to say something about those variables but, here, you don't say anything about them! What you have on the right side of your "=" is a number (its value depending on the value of "R"). The left side must be a single number, not several different numbers. You say "q, w, e, 1 over r and minus t equal something". Again, q, w, e, 1/r, and -t are 5 possibl6 different numbers. They may not all be equal to that "something". If that is your intent, that q, w, e, 1/r, and -t are each equal to 10log(4\piR^{2}) then you need to write 5 different equations:
q= 10log(4\piR^{2})
w= 10log(4\piR^{2})
e= 10log(4\piR^{2})
1/r= 10log(4\piR^{2}) and
-t= 10log(4\piR^{2}).
(It is legitimate to write that as "q= w= e= 1/r= -t= 10log(4\piR^{2})". That is just "shorthand" for the 5 different equations but it may be what you are talking about.)

If, instead, you mean that some algebraic combination of those 5 variables equals 10log(4\piR^{2}), then write that algebraic combination of the variables equal to 10log(4\piR^{2}). If you mean that there is some unknown combination equal to 10log(4\piR^{2}) write f(e, q, w, 1/r, -t)= 10log(4\piR^{2}) where the function "f" is the unknown combination. (and since the unknown combination might involve inverting 1/r or multiplying -t by -1, it could as well be written f(e, q, w, r, t)= 10log(4\piR^{2}).)

HallsofIvy
 
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