Is the Derivative of an Inverse Function Valid? Insights and Links!

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Discussion Overview

The discussion centers around the validity of the proof for the derivative of an inverse function, exploring different methods of proof, including the chain rule and the definition of the derivative. Participants express confusion regarding the application of these methods and seek clarification on specific points related to the proof.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant expresses understanding of the proof using the derivative definition but questions its validity and seeks additional resources for clarification.
  • Another participant agrees that the proof appears valid but notes potential confusion regarding the roles of variables x and y in the proof.
  • A later reply humorously suggests that one participant's notation may imply an imaginary component, adding a light-hearted element to the discussion.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the validity of the proof, with some agreeing it looks valid while others express confusion about specific aspects of the proof.

Contextual Notes

There is ambiguity regarding the use of variables x and y in the proof, which may affect participants' understanding. Additionally, the discussion does not resolve the question of whether the proof is valid.

Petrus
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Hello MHB,
I am aware of there is two way, u can use chain rule or defination of derivate. I totally understand the proof with this type Derivative of Inverse Function but is that a valid proof? How ever our teacher did proof this with derivate defination which I don't understand from my textbook. What is your thought? Any good link that explain this proof with derivate defination

I am aware that we use chain rule and I am training for oral exam and I guess I will have to proof this chain rule in this one.

edit: why should $$f'(x) \neq 0$$ should it be $$f'(y) \neq 0$$
Regards,
$$|\pi\rangle$$
 
Last edited:
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re: proof of inverse derivative

Petrus said:
Hello MHB,
I am aware of there is two way, u can use chain rule or defination of derivate. I totally understand the proof with this type Derivative of Inverse Function but is that a valid proof? How ever our teacher did proof this with derivate defination which I don't understand from my textbook. What is your thought? Any good link that explain this proof with derivate defination

I am aware that we use chain rule and I am training for oral exam and I guess I will have to proof this chain rule in this one.

edit: why should $$f'(x) \neq 0$$ should it be $$f'(y) \neq 0$$
Regards,
$$|\pi\rangle$$

That proof looks valid to me.

Note that there may be some confusion about x and y, since their meanings are swapped around after the first line.
In the first line x is used as the argument of f, but in the second line and thereafter x is used as the argument of $f^{-1}$ instead (where you might expect y to be the argument).
 
Re: proof of inverse derivative

I like Serena said:
That proof looks valid to me.

Note that there may be some confusion about x and y, since their meanings are swapped around after the first line.
In the first line x is used as the argument of f, but in the second line and thereafter x is used as the argument of $f^{-1}$ instead (where you might expect y to be the argument).
Thanks for taking your time I like Serena!:)

PS. Should I be rational or real:p

Regards,
$$|\pi\rangle$$
 
Re: proof of inverse derivative

Petrus said:
Thanks for taking your time I like Serena!:)

PS. Should I be rational or real:p

Regards,
$$|\pi\rangle$$

I think that $$|\pi\rangle$$ is imaginary. (Pizza)
 

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