How to differentiate f(x)=2sin(x)+2x^x?

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    Differentiation
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Discussion Overview

The discussion centers on the differentiation of the function f(x) = 2sin(x) + 2x^x, exploring various methods and interpretations of the differentiation process. The scope includes mathematical reasoning and technical explanation related to calculus.

Discussion Character

  • Technical explanation, Mathematical reasoning, Debate/contested

Main Points Raised

  • One participant suggests that x^x can be expressed as exp{x log x}, indicating a method for differentiation based on this transformation.
  • Another participant provides a detailed implicit differentiation approach, stating that the derivative of x^x is h'(x) = (x^x)(lnx + 1), leading to a proposed derivative for f(x) as f'(x) = 2cos(x) + 2(x^x)(lnx + 1).
  • A different participant claims the derivative is f'(x) = 2cos(x) + 2e^(xlnx), asserting that the chain rule must be applied to the last term, which introduces a correction to the previous claim.

Areas of Agreement / Disagreement

Participants express differing views on the correct application of differentiation techniques, particularly regarding the term 2x^x. There is no consensus on the final derivative, as multiple interpretations and methods are presented.

Contextual Notes

Some participants reference specific differentiation rules and methods, but there are unresolved aspects regarding the application of the chain rule and the interpretation of the function x^x.

dbzgtjh
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can anyone tell me how to differentiate this function f(x)=2sin(x)+2x^x?
 
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x^x is the same as exp{xlogx}

you can now differentiate using the basic results you've been taught.
 
Hello, dbzgtjh!
First of all, we must know how to differentiate this function:
[f(x)]^g(x) = h(x), so, ln{[f(x)]^g(x)} = ln h(x), is equal to
g(x)lnf(x) = ln h(x)
differentiating implicitly, we have, g'(x)lnf(x) + g(x)f'(x)/f(x) = h'(x)/h(x),
therefore,
h'(x) = h(x) [ g'(x)lnf(x) + g(x)f'(x)/f(x) ]
In this case g(x) = x = f(x), so
h(x) = x^x, so h'(x) = (x^x)(lnx + 1)
Therefore,
the derivative of function f is f'(x) = 2cosx + 2(x^x)(lnx + 1).
 
Last edited:
kastarov said:
Hello, dbzgtjh!
Differential function is f'(x) = 2cos(x)+2e^(xlnx). Any doubt look for a textbook, for example:
Calculus; Stewart, James. v.1
This is incorrect; you must apply the chain rule on the last term.
 

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