Math Is Fun Forum

Hixy

Member

Registered: 2011-09-24

Posts: 15

Explanation of solution steps

In a physics problem, we end up with the expression

The wording of the solution is like so:
"Expanding this to first order in dy gives

What does this mean and how was this 'expansion' performed?

There are still a few english mathematical terms that I'm unfamiliar with. I apologize if this question is too trivial.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,621

Re: Explanation of solution steps

hi Hixy,

I think like this:

The left hand side is just what we mean by dT/dy so

Not sure why the word 'expanding' is used.

Pure mathematicians will be holding the heads in their hands in horror at the way the differential notation has been abused here, but, subject to some conditions, it kinda works out ok in the end.  That's physicists for you. 

Oh yes, just spotted it.  Substitute 'rho' for 'p' throughout.

And oh yes, nothing wrong with your English.  It's the physicists use of English that is in question.

Bob

Last edited by Bob (2011-10-09 23:50:24)

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

Hixy

Member

Registered: 2011-09-24

Posts: 15

Re: Explanation of solution steps

Hahaha, yeah.. That is indeed abusive! Thanks for the quick and illustrative reply

Bob

Administrator

Registered: 2010-06-20

Posts: 10,621

Re: Explanation of solution steps

You are welcome. 

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob