Using implicit differentiation to differentiate log_a (x)

In summary, the conversation discussed finding the derivative of the logarithm to the base a of x using implicit differentiation. The process involved using the chain rule and simplifying to find the final equation for the derivative. The final result was \frac{dy}{dx} = \frac{1}{x \ln a}.
  • #1
endeavor
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Could someone please make sure I'm doing this right.
I want to find the derivative of the logarithm to the base a of x, using implicit differentiation.

Let [tex]y = \log_{a} x[/tex]

[tex]a^y = x[/tex]

[tex]\frac{d}{dx} (a^y) = 1[/tex] (implicit differentiation)

[tex]\frac{d}{dx} (e^{\ln a})^y = 1[/tex]

[tex]\frac{d}{dx} (e^{(\ln a)y}) = 1[/tex]

[tex]e^{(\ln a)y} \frac{d}{dx} ((\ln a)(y)) = 1[/tex]

[tex](e^{\ln a})^y \frac{d}{dy} ((\ln a)(y)) \frac{dy}{dx} = 1[/tex] (did I use the chain rule correctly here?)

[tex](a^y)(\ln a) \frac{dy}{dx} = 1[/tex]

[tex]x \ln a \frac{dy}{dx} = 1[/tex]

[tex]\frac{dy}{dx} = \frac{1}{x \ln a}[/tex]
 
Last edited:
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  • #2
Yep, very nicely done!
 

Related to Using implicit differentiation to differentiate log_a (x)

1. What is implicit differentiation?

Implicit differentiation is a mathematical technique used to find the derivative of a function that is not explicitly written in terms of one variable. This is useful when the function cannot be easily solved for one variable, such as in the case of logarithmic functions.

2. How do you use implicit differentiation to differentiate loga(x)?

To differentiate loga(x) using implicit differentiation, you first need to differentiate both sides of the equation with respect to x. Then, use the chain rule to differentiate the loga(x) term, and solve for dy/dx.

3. What is the chain rule in implicit differentiation?

The chain rule in implicit differentiation states that when differentiating a composite function, you need to multiply the derivative of the outer function by the derivative of the inner function.

4. Can implicit differentiation be used for any function?

Yes, implicit differentiation can be used for any function that is not explicitly written in terms of one variable. However, it is most commonly used for functions involving logarithms, exponential, and trigonometric functions.

5. Why is implicit differentiation useful?

Implicit differentiation is useful because it allows us to find the derivative of a function even when it cannot be easily solved for one variable. It is also helpful in finding the derivative of inverse functions and in solving related rates problems in calculus.

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