Back to School: Analyzing e^x and its Variations

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Discussion Overview

The discussion revolves around the classification of the function e^x and its variations as even or odd functions. Participants explore definitions, apply mathematical reasoning, and consider graphical interpretations.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant questions whether e^x is an even or odd function.
  • Another suggests applying the definitions of even and odd functions to analyze e^x.
  • A participant reports difficulty in applying the definitions, noting that substituting -x into e^x yields (1/e^x), which does not satisfy the conditions for even or odd functions.
  • It is stated that a function is even if f(-x) = f(x) and odd if f(-x) = -f(x), with examples provided (cos(x) for even and sin(x) for odd).
  • Participants note that e^x is neither even nor odd, while e^x + e^-x is classified as even and e^x - e^-x as odd, with references to their relationships to cosine and sine functions, respectively.
  • Graphical symmetry is proposed as an alternative method to determine the nature of the functions.
  • It is mentioned that a function can be neither even nor odd.

Areas of Agreement / Disagreement

Participants express differing views on the classification of e^x, with some asserting it is neither even nor odd, while others agree on the classifications of e^x + e^-x as even and e^x - e^-x as odd. The discussion remains unresolved regarding the initial question about e^x.

Contextual Notes

Participants rely on definitions of even and odd functions, but there are indications of confusion regarding the application of these definitions to e^x. The discussion does not resolve the mathematical steps involved in the analysis.

thenewbosco
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just starting up the school year again and my brain is not there yet.

Is e^x an even or odd function.

also what about
e^x + e^-x

and

e^x - e^-x

thanks for the help.
 
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Have you tried to apply the definitions of even and odd functions? Where does it get you?
 
it gets me nowhere. applying the definition and inserting -x into e^x just gives (1/e^x) which is neither f(x) nor -f(x).
 
a function is even iff f(-x) = f(x), for example cos(x)
a function is odd iff f(-x) = -f(x), for example sin(x)

exp(-x) <> exp(x) <> -exp(x), so exp(x) is neither
exp(-x)+exp(x) = exp(x)+exp(-x), so exp(x)+exp(-x) is even (=2cos(x))
exp(-x)-exp(x) = -(exp(x)-exp(-x)), so exp(x)-exp(-x) is odd (=2isin(x))
 
Another approach, graphically. An even function is symmetric to the y-axis, an odd function symmetric to the origin. Graph you functions and see what you come up with.
 
thenewbosco said:
...which is neither f(x) nor -f(x).

It's possible for a function to be neither even nor odd.
 

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