Derivative of log proof question

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SUMMARY

The derivative of the logarithm function with base \( b \) is expressed as \( \frac{d}{dx} [\log_{b}x] = \frac{1}{\ln b} \cdot \frac{1}{x} \) for \( x > 0 \). This derivation utilizes the constant multiple rule, where \( \frac{1}{\ln b} \) is treated as a constant factor during differentiation. The proof confirms that \( \ln b \) acts similarly to any constant, allowing it to be factored out while differentiating \( \ln x \).

PREREQUISITES
  • Understanding of basic calculus principles, specifically differentiation.
  • Familiarity with logarithmic functions and their properties.
  • Knowledge of the natural logarithm and its relationship to logarithms of other bases.
  • Concept of constant factors in differentiation.
NEXT STEPS
  • Study the constant multiple rule in calculus for deeper insights.
  • Explore the properties of logarithmic functions, including change of base formulas.
  • Learn about the applications of derivatives in real-world scenarios.
  • Investigate advanced differentiation techniques, such as implicit differentiation.
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Students studying calculus, mathematics educators, and anyone looking to strengthen their understanding of logarithmic differentiation.

LearninDaMath
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Proof

d/dx [log[itex]_{b}x[/itex]] = d/dx (lnx/lnb) = 1/lnb d/dx(lnx) = 1/xlnb , when x>0


I think I see the constant multiple rule at work here, but why? Is it because 1/lnb is a constant, so it is "factored" out of lnx/lnb and treated as a constant while lnx is treated as the term to be differentiated?
 
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LearninDaMath said:
Proof

d/dx [log[itex]_{b}x[/itex]] = d/dx (lnx/lnb) = 1/lnb d/dx(lnx) = 1/xlnb , when x>0


I think I see the constant multiple rule at work here, but why? Is it because 1/lnb is a constant, so it is "factored" out of lnx/lnb and treated as a constant while lnx is treated as the term to be differentiated?

Exactly. ln(b) is just a constant factor, like 2.
 
Dick said:
Exactly. ln(b) is just a constant factor, like 2.

cool thanks
 

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