Proof of Identity: Differentiating $\alpha^ax$ and $\alpha^by$

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In summary, the given conversation is about differentiating a left side with the help of the chain rule and the Euler's Homogeneous Function Theorem. The equation \alpha\frac{d}{d\alpha}[f(\alpha^ax,\alpha^by)]|_{\alpha=1}=ax\frac{\partial f}{\partial x}+by\frac{\partial f}{\partial y} is discussed, along with the use of multi-variable functions and the meaning of \frac{\partial f}{\partial x}. The conversation ends with asking for help in understanding the problem.
  • #1
matematikuvol
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Homework Statement


[tex]\alpha\frac{d}{d\alpha}[f(\alpha^ax,\alpha^by)]|_{\alpha=1}=ax\frac{\partial f}{\partial x}+by\frac{\partial f}{\partial y}[/tex]


Homework Equations





The Attempt at a Solution


Homework Statement


I'm confused. I don't know what to do here. How to differentiate left side? Thanks for your help.
 
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  • #2
You have to use the chain rule for multi-variable functions. Try it out and if you get stuck post what you've done
 
  • #3
For example

[tex]\frac{d}{d\alpha}f(\alpha^ax)=ax\alpha^{a-1}\frac{\partial f}{\partial \alpha}[/tex]

Right?
 
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  • #4
Well,
[tex]\frac{\partial f}{\alpha}[/tex]
is meaningless. Was that a typo? What did you mean? Perhaps
[tex]\frac{\partial f}{\partial x}[/tex]?
 
  • #5
Sorry. I made a mistake. You can see know what I meant. I edit my last message.
 
  • #6
matematikuvol said:

Homework Statement


[tex]\alpha\frac{d}{d\alpha}[f(\alpha^ax,\alpha^by)]|_{\alpha=1}=ax\frac{\partial f}{\partial x}+by\frac{\partial f}{\partial y}[/tex]

Homework Equations



The Attempt at a Solution


Homework Statement


I'm confused. I don't know what to do here. How to differentiate left side? Thanks for your help.
It would help if you would give us the whole problem, word for word as it was given to you.

For instance, what is meant by [itex]\displaystyle\frac{\partial f}{\partial x}\,?[/itex]

I assume that's [itex]\displaystyle\frac{\partial f(x,\,y)}{\partial x}\,,[/itex] evaluated at (x, y) = (αax, αby) rather than [itex]\displaystyle\frac{\partial f(\alpha^a x,\, \alpha^b y)}{\partial x}\,.[/itex]​
 
  • #7
I'm not quite sure. I had only left side. So
[tex]\alpha\frac{d}{d\alpha}[f(\alpha^a x,\alpha^by)]|\alpha=1=[/tex]
Please help if you know. I'm confused.
 

1. What is the purpose of differentiating $\alpha^ax$ and $\alpha^by$ in proof of identity?

The purpose of differentiating $\alpha^ax$ and $\alpha^by$ is to show that they are not equivalent and cannot be simplified or combined. This is important in proving the validity of an identity in mathematics.

2. How do you differentiate between $\alpha^ax$ and $\alpha^by$?

In order to differentiate between $\alpha^ax$ and $\alpha^by$, you need to compare the exponents. If the exponents (a and b) are different, then the terms cannot be simplified. Additionally, you can also check if the bases (alpha) are the same or different.

3. Can $\alpha^ax$ and $\alpha^by$ ever be equivalent?

No, $\alpha^ax$ and $\alpha^by$ can never be equivalent since they have different exponents. Even if the bases are the same, the different exponents make the terms different and therefore not equivalent.

4. Why is it important to differentiate $\alpha^ax$ and $\alpha^by$ in proof of identity?

Differentiating $\alpha^ax$ and $\alpha^by$ is important because it helps to prove the validity of an identity. By showing that these terms are not equivalent, it demonstrates that the identity cannot be simplified or reduced further.

5. How does differentiating $\alpha^ax$ and $\alpha^by$ relate to the concept of variables in mathematics?

Differentiating $\alpha^ax$ and $\alpha^by$ is an important concept in mathematics because it helps to understand the role of variables in equations and identities. By recognizing that these terms cannot be combined, it reinforces the idea that variables represent unknown quantities and cannot be simplified or combined unless they are like terms.

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