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#1 2012-10-21 21:11:01
- zetafunc.
- Guest
Partial Derivative Proof
I came across an interesting tool which would help for differentiating functions involving x and y;
where f is a function of x and y and the deltas denote partial derivatives.
But why is this the case?
#2 2012-10-21 21:55:38
- bobbym
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Re: Partial Derivative Proof
Hi zetafunc.;
I know about that one. It is useful for implicit functions.
In mathematics, you don't understand things. You just get used to them.
90% of mathematicians do not understand 90% of currently published mathematics.
I am willing to wager that over 75% of the new words that appeared were nothing more than spelling errors that caught on.
#3 2012-10-21 21:56:55
- zetafunc.
- Guest
Re: Partial Derivative Proof
Yes, I agree. It was useful for solving the ODEs we were given in class when we had to differentiate annoying functions twice and sub initial conditions, etc... do you remember how it is derived?
#4 2012-10-21 22:03:33
- bobbym
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Re: Partial Derivative Proof
Hi;
That I do not. I will see if I can find anything.
In mathematics, you don't understand things. You just get used to them.
90% of mathematicians do not understand 90% of currently published mathematics.
I am willing to wager that over 75% of the new words that appeared were nothing more than spelling errors that caught on.
#5 2012-10-21 22:15:51
- zetafunc.
- Guest
Re: Partial Derivative Proof
Thanks. I am particularly confused by the minus sign.
#6 2012-10-21 22:44:37
- bobbym
- Administrator
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Re: Partial Derivative Proof
Hi;
Check here about half way down.
http://www.solitaryroad.com/c352.html
In mathematics, you don't understand things. You just get used to them.
90% of mathematicians do not understand 90% of currently published mathematics.
I am willing to wager that over 75% of the new words that appeared were nothing more than spelling errors that caught on.
#7 2012-10-21 22:59:31
- zetafunc.
- Guest
Re: Partial Derivative Proof
As part of the proof, they are saying that
is the total differential of the function f(x,y). Why?
#8 2012-10-21 23:05:34
- bobbym
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Re: Partial Derivative Proof
Hi;
Over here he calls it a definition.
http://www.ltcconline.net/greenl/course … iffere.htm
In mathematics, you don't understand things. You just get used to them.
90% of mathematicians do not understand 90% of currently published mathematics.
I am willing to wager that over 75% of the new words that appeared were nothing more than spelling errors that caught on.
#9 2012-10-21 23:28:31
- zetafunc.
- Guest
Re: Partial Derivative Proof
Hmm. I think maybe that comes from an illustration.
#10 2012-10-22 01:25:47
- bobbym
- Administrator
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Re: Partial Derivative Proof
It looks like it comes from the total derivative but I can not understand their notation so I can not derive it.
In mathematics, you don't understand things. You just get used to them.
90% of mathematicians do not understand 90% of currently published mathematics.
I am willing to wager that over 75% of the new words that appeared were nothing more than spelling errors that caught on.