Analysis Proof: Sum of odd and even functions.

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Homework Help Overview

The discussion revolves around expressing a function f(x) as the sum of an even function E(x) and an odd function O(x). The specific case being analyzed is when f(x) is defined as e^x, with the assumption that the domain is symmetric about 0.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants explore how to express f(x) as a sum of even and odd functions, questioning whether the expression derived represents such a sum. There is an attempt to substitute e^x into the equation to see the resulting functions.

Discussion Status

Participants are actively engaging with the problem, with some suggesting substitutions and others verifying the equality of expressions. There is a recognition of the relationship between e^x, cosh(x), and sinh(x) as representations of even and odd functions, but no consensus has been reached on the implications of these findings.

Contextual Notes

Participants are working under the assumption that f(x) is defined for all x and that the domain is symmetric about 0. There is an ongoing exploration of the definitions of even and odd functions in this context.

The_Iceflash
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Homework Statement


Show f(x) can be expressed as the sum of E(x) and an odd function O(x).

f(x) is defined for all x (assume domain D symmetric about 0)

f(x) = \frac{f(x)+f(-x}{2}
Then:
How does it look if f(x) = e^x?

Homework Equations


N/A


The Attempt at a Solution



So I got \frac{f(x)+f(-x)+f(x)-f(-x)}{2}

as my solution for that.

From that I need to answer: How does it look if f(x) = e^x ? I'm not sure what to do to show that.
 
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The_Iceflash said:

Homework Statement


Show f(x) can be expressed as the sum of E(x) and an odd function O(x).

f(x) is defined for all x (assume domain D symmetric about 0)

f(x) = \frac{f(x)+f(-x}{2}
Then:
How does it look if f(x) = e^x?

Homework Equations


N/A


The Attempt at a Solution



So I got \frac{f(x)+f(-x)+f(x)-f(-x)}{2}

as my solution for that.

From that I need to answer: How does it look if f(x) = e^x ? I'm not sure what to do to show that.

First: Is that a sum of odd and even functions?

Second: Well, try sticking e^x in for f(x) and see what functions you get.
 
Char. Limit said:
First: Is that a sum of odd and even functions?

Second: Well, try sticking e^x in for f(x) and see what functions you get.

I stuck in e^x for f(x) and got e^x. Is this supposed to represent something?
 
You should get...

f(x)=\frac{e^x+e^{-x}}{2}
 
Well, since the two sides are equal I would hope you get ex back when you cancel everything. But notice without canceling what you get

e^x = \frac{e^x+e^{-x}}{2} + \frac{e^x-e^{-x}}{2} = cosh(x)+sinh(x) which is a way of writing e^x as a sum of an odd and an even function
 

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