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Differentiating a function with multiple variables?

tomas giud
Posted 10 years ago

I have problems when trying to differentite Zbeta respect to b and then defining a function with Zbeta respect to other variable which was a parameter... how's the proper way to proceed?

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POSTED BY: tomas giud
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Bill Simpson
Bill Simpson
Posted 10 years ago
POSTED BY: Bill Simpson
tomas giud
tomas giud
Posted 10 years ago

If after the third line I ask the value of D[L[b], b] I get an expression wich has both b and e. Then why can´t I define a function with argument e_ calling the latter expression on the right hand side ...if i directly write the expresion, it works! but if i call the equivalent expression it doesn't! I do know that defining functions require to have the same symbol on both sides of the definition I also know that what i said fixes my problem, but I can't understand why it's a problem in the first place. why does mathematica makes a difference
POSTED BY: tomas giud
Bill Simpson
Bill Simpson
Posted 10 years ago

If you compare

FullForm[?prom[e]]

with

FullForm[?prom[f]]

you should notice that the two are the same. You might think that one should have replaced all the "e" with "f".

I believe your problems are caused by your use of one symbol as a pattern on the left hand side of your function definition, but not having that symbol appear on the right hand side. I believe you are assuming that your "e" on the left hand side is going to leak across and through several function definitions to get to the e in the previous definitions. That doesn't appear to be happening.

From this description try writing a few other function definitions that do and do not use the same symbol name on both the left and right hand sides of a single function and see if you can begin to guess what kinds of function definition and parameter naming will work.
POSTED BY: Bill Simpson
tomas giud
tomas giud
Posted 10 years ago

I can't figure why [Epsilon]prom2[e_] := [Epsilon]prom[e] /. b -> [Beta] gives an expression appearently usefull but when evaluating epsilonprom2[3] it does nothing at all
POSTED BY: tomas giud
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