Natural log (ln x) derivative question

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SUMMARY

The derivative of the function y = ln(ln(ln(x))) is calculated using the chain rule. The correct notation for the derivative is dy/dx, not ∂y/∂x, as the latter refers to partial derivatives. The initial assumption that the derivative is 1/x is incorrect; instead, the derivative requires multiple applications of the chain rule to account for the composite nature of the function.

PREREQUISITES
  • Understanding of derivatives and the chain rule in calculus
  • Familiarity with logarithmic functions and their properties
  • Knowledge of notation for derivatives (dy/dx vs. ∂y/∂x)
  • Basic algebra skills for manipulating composite functions
NEXT STEPS
  • Study the chain rule in calculus for composite functions
  • Practice calculating derivatives of nested logarithmic functions
  • Review the differences between ordinary derivatives and partial derivatives
  • Explore examples of applying the chain rule in various contexts
USEFUL FOR

Students studying calculus, particularly those learning about derivatives and logarithmic functions, as well as educators looking for examples of common misconceptions in derivative notation.

SteveM19
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Homework Statement



This is to help out a 40something calc student -- thank you all in advance for your help


Homework Equations



If f (y) = ln ln ln x, what is ∂y/∂x?

The Attempt at a Solution



I came up with 1/x, which I got by applying ∂y/∂x ln x = 1/x three times, is this right? Thank you again for your help.
 
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Is that a ##f(y)##? Or like ##f(x) = y =~ ...##
 
BloodyFrozen said:
Is that a ##f(y)##? Or like ##f(x) = y =~ ...##

I might have used the terminology incorrectly --

y = ln ln ln x

What is y prime?
 
SteveM19 said:

Homework Statement



This is to help out a 40something calc student -- thank you all in advance for your help

Homework Equations



If f (y) = ln ln ln x, what is ∂y/∂x?
As BloodyFrozen already noted, that should be f(x) = ...

Also, the problem should be asking for dy/dx, not ∂y/∂x, which is the partial derivative of y with respect to x. Unless I'm missing something, you want the ordinary derivative, dy/dx.
SteveM19 said:

The Attempt at a Solution



I came up with 1/x, which I got by applying ∂y/∂x ln x = 1/x three times, is this right? Thank you again for your help.
No, it's not right. You have a composite function, y = ln(ln(ln(x))), so you need to use the chain rule a couple of times. It also might be helpful to include parentheses as I did.In response to your other question, you can take y' to be a synonym of dy/dx.
 

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