Need help on how to prove a function is odd.

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In summary, the conversation is about proving the function f(x) is odd. The person is struggling with the specific form of the function and asks for help. The other person reminds them of the definition of an odd function and suggests evaluating f(-x) to prove it.
  • #1
DennyCrane
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I need to prove f(x)=x/x^2+1

I'm not sure how to because I never do this with fractions and it's just messed me up. Any help is appreciated.
 
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  • #2
Welcome to PF!

THis looks like homework and we have forum rules that it must be submitted using the homework template. If you look at other posts you should see how its done.

Next:

DId you write the equation correctly is it?

f(x) = (x/x^2) + 1

or is it?

f(x) = x / (x^2 + 1)

I think you meant the 2nd one, right?

Now:

What is the definition of an odd function?
 
  • #3
DennyCrane said:
I need to prove f(x)=x/x^2+1

I'm not sure how to because I never do this with fractions and it's just messed me up. Any help is appreciated.

IDK why the particular form of this function is tripping you up.

To prove f(x) is odd, you must show is that -f(x) = f(-x), for all x and -x in the domain of f.

http://en.wikipedia.org/wiki/Even_and_odd_functions

What happens when you evaluate f(-x) for this function?
 

What does it mean for a function to be odd?

A function is considered odd if it satisfies the following conditions:

  • The function is defined for all real numbers
  • The function is symmetric about the origin (0,0)
  • The function satisfies the property f(-x) = -f(x) for all x

In simpler terms, an odd function is one that has a graph that is symmetrical about the origin and has opposite outputs for opposite inputs.

How do I prove that a function is odd?

To prove that a function is odd, you must show that it satisfies the three conditions mentioned earlier:

  • The function is defined for all real numbers
  • The function is symmetric about the origin (0,0)
  • The function satisfies the property f(-x) = -f(x) for all x

This can be done through various methods such as showing that the graph is symmetrical, using algebraic manipulation, or using the definition of an odd function.

What is the significance of proving that a function is odd?

Proving that a function is odd is important because it allows us to make certain simplifications and predictions about the function. For example, we can use the fact that an odd function has a graph that is symmetrical to find the value of a function at a certain point by using the value of its reflection. Additionally, we can also use the properties of odd functions to solve equations involving these functions.

Can a function be both even and odd?

No, a function cannot be both even and odd. By definition, an even function is one that is symmetric about the y-axis (x=0) and satisfies the property f(x) = f(-x) for all x. On the other hand, an odd function is symmetric about the origin (0,0) and satisfies the property f(-x) = -f(x) for all x. These two conditions cannot be satisfied simultaneously, therefore a function cannot be both even and odd.

What are some common examples of odd functions?

Some common examples of odd functions include:

  • f(x) = x
  • f(x) = x^3
  • f(x) = sin(x)
  • f(x) = tan(x)

These functions can be identified as odd by showing that they satisfy the three conditions mentioned earlier: defined for all real numbers, symmetric about the origin, and satisfying the property f(-x) = -f(x) for all x.

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