Parameter and arbitrary

[EvoN1020v]

Can anybody explain to me what is the difference between parameter and arbitrary?

[matt grime]

Look in a dictionary, for they are used in maths as their common english usage. oone is a noun the the other an adjective. that is sufficient difference between them

[EvoN1020v]

hey matt grime, why would I ask such a question? I have already search for defintions of those words, and I understand abit of what parameter is. I have done some works in my math class on that, but I have no concept of what an arbitrary is. Can you explain it, and give me an example?

[matt grime]

You didn't ask for a definition. And as i said, arbitrary is an adjective it is not a noun, it doesn't make sense to ask what "an arbitrary" is. Seriously, find a dictionary and look it up; it's not maths, and i guess that English isn't your first language so rather than you have to mistranslate my words just look them up in the library, or use babelfish.

 

If you want to do it by example: Let P be a proposition, then P(x) is true for arbitrary x if it is true for all x for which it makes sense to ask for P(x).

 

As you can see it has nothing to do with parameters, that is why your question is impossibly difficult to answer sensibly. It is like asking someone to define the difference between 'fish' and 'fast'.

[Tannin]

Dear EvoN1020v

Perhaps, if you show us the context in which you have seen the words "parameter" and "arbitrary", it would be easier to explain the difference.

Regards,

Tannin

[EvoN1020v]

Ok I looked up on http://www.dictionary.com for "arbitrary": "Determined by chance, whim, or impulse, and not by necessity, reason, or principle: stopped at the first motel we passed, an arbitrary choice.".

 

I don't really understand?

[matt grime]

I gave you the mathematical usage.

 

'Arbitrary' is used in proving things 'for all' objects of some kind, it has nothing to do with parameters.

 

Further example: suppose i let x be in N and prove some result (say x^2+x is even) depending on nothing to do with *which* x i picked, then I would say that the result is true for all x in N since my choice of x was *arbitrary*.

 

This is analogous to the choice of the first motel. There was no compelling reason to pick 'the first', the choice of the first was arbitrary, my choice of x was arbitray.