The derivative of 4^x + 3^x + 9^-x would be zero.

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Homework Help Overview

The discussion revolves around finding the derivative of the expression 4^x + 3^x + 9^-x, with participants exploring the implications of the derivative potentially being zero.

Discussion Character

  • Mathematical reasoning, Conceptual clarification

Approaches and Questions Raised

  • Participants discuss the general formula for differentiating exponential functions, with references to the logarithmic properties involved. There are attempts to clarify the process of differentiation and its application to the given expression.

Discussion Status

Some participants have provided insights into the differentiation process for exponential functions, while others express confusion regarding the implications of the derivative being zero. Multiple interpretations of the problem are being explored.

Contextual Notes

There appears to be some uncertainty regarding the application of the derivative rules to the specific terms in the expression, as well as the conditions under which the derivative could equal zero.

EvilPony
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if anyone can teach me how to do this that would be great, thanks.

dereiv. means derivative sorry
 
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EvilPony said:
if anyone can teach me how to do this that would be great, thanks.

dereiv. means derivative sorry

when I am doing something with the form something raised to x i always remember - keep the tern , log (or ln, same meaning here) the base number

and then differentiate the exponent

for example for [tex]\frac{d}{dx} (3^x) = 3^x Log3 (1)[/tex]

as you can see keep the function 3^x, log the base Log3, and then differentiate the numerator (1).
 
All I can say to the above post, is eh? That would mean that it would be 0. In general:

[tex]\frac{d}{dx} \left( a^x \right) = \ln (a) \; a^x[/tex]

Where a is some constant. Here is the method used to work it out and generally useful for this type of problem:

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

[tex]\ln y = \ln \left( a^x \right)[/tex]

[tex]\ln y = x \ln a[/tex]

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

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

[tex]\frac{d}{dx} \left( a^x \right) = \ln (a) \; a^x[/tex]
 
Zurtex said:
All I can say to the above post, is eh? That would mean that it would be 0. In general:

[tex]\frac{d}{dx} \left( a^x \right) = \ln (a) \; a^x[/tex]

Where a is some constant. Here is the method used to work it out and generally useful for this type of problem:

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

[tex]\ln y = \ln \left( a^x \right)[/tex]

[tex]\ln y = x \ln a[/tex]

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

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

[tex]\frac{d}{dx} \left( a^x \right) = \ln (a) \; a^x[/tex]
what would be zero??
 

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