Find f(x) Function: What is a One-to-One Function?

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Discussion Overview

The discussion revolves around the concept of one-to-one functions in mathematics, specifically exploring the conditions under which a function F can be defined such that the composition with another function g results in the identity function, while a different composition with a function h does not. The scope includes theoretical understanding and examples of one-to-one functions.

Discussion Character

  • Conceptual clarification
  • Homework-related
  • Mathematical reasoning

Main Points Raised

  • One participant asks for help in finding a function F such that the composition fog equals the identity function, while hof does not hold true for some function h.
  • Another participant provides a link to a resource on functions, suggesting that understanding the basics is necessary to answer the question.
  • A participant explains that a one-to-one function means that f(a) does not equal f(b) unless a equals b, using the example of the function x² being two-to-one except at x = 0.
  • One participant proposes F(x) = 3x + 2 and g(x) = x/3 - 2/3 as functions that satisfy the condition fog = I, while stating that if h(x) = x², then hof = I is not true.
  • Another participant agrees with the previous statement, clarifying that if h and f are defined on the whole real line, there cannot be a function f such that f°h = I or h°f = I.

Areas of Agreement / Disagreement

Participants express varying levels of understanding regarding one-to-one functions, with some agreeing on the definitions and examples provided, while the initial question about finding the function F remains unresolved.

Contextual Notes

There are limitations in the discussion regarding the definitions of functions and the specific conditions under which the compositions are evaluated. The mathematical steps leading to the conclusion about the impossibility of certain compositions are not fully explored.

Who May Find This Useful

This discussion may be useful for students learning about functions, particularly those interested in the properties of one-to-one functions and their compositions.

furi0n
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i have seen it before and i coudn't answer.
if F is function such that fog=I(one to one function) for some g function but hof=I isn't true for h is some functıon then Find F(x) function.
if solve this problem, please give me some link which explains what One to one function is maybe ı don't know exactly this function style. I'm waiting for your answer thanks..
 
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hi furi0n! :smile:

"one-to-one" means that it doesn't repeat … f(a) is not the same as f(b) unless a = b

(so, for example, x2 would be a two-to-one function, except at x = 0, because x2 = (-x)2 :wink:)
 
hmmm :)
so, if F(x)= 3x+2 g(x)=x/3-2/3 then Fog=I and if H(x)=x^2 then hof=I isn't true.
excuse me to ask this question but now I'm new student and i want to learn what i don't know. thank you everybody.:)
 
furi0n said:
so, if F(x)= 3x+2 g(x)=x/3-2/3 then Fog=I and if H(x)=x^2 then hof=I isn't true.

Yes, if h(x) = x2, and if h and f are defined on the whole real line, then there's no f such that f°h = I or h°f = I.
 
thanks a lot
 

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