Bijective Function: f: [0,1] --> [0,1]

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In summary, the function in question is bijective if and only if the values of x1 and x2 are either both rational or both irrational. Otherwise, one of the values will be rational while the other is irrational, making the function not bijective.
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CarmineCortez
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Is this function bijective ?

f: [0,1] --> [0,1] f(x) = x if x E [0,1] intersection Q
f(x) = 1-x if x E [0,1]\Q
 
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The question then is whether it is possible to get f(x1)= f(x2) for two different values of x1, x2 in [0, 1]. If both are rational, then that says x1= x2 so that case cannot happen. If both are irrational, then 1-x1= 1-x2 which also leads to x1= x2. If x1 is rational and x2 irrational, then x1= 1- x2 or if x1 is irrational and x2 rational, 1-x1= x2.

Do you see that in both cases one of f(x1), f(x2) is rational and the other irrational?
 

1. What is a bijective function?

A bijective function is a type of mathematical function that has a one-to-one correspondence between its input and output values. This means that for every input, there is a unique output, and for every output, there is a unique input.

2. What does the notation f: [0,1] --> [0,1] mean?

The notation f: [0,1] --> [0,1] specifies the domain and codomain of the bijective function. In this case, the function takes inputs from the interval [0,1] and outputs values also in the interval [0,1].

3. How is a bijective function different from other types of functions?

A bijective function is different from other types of functions because it has a one-to-one correspondence between its input and output values. This means that the function is both injective (one-to-one) and surjective (onto).

4. Can a bijective function have a different domain and codomain?

Yes, a bijective function can have a different domain and codomain. The important aspect is that there is a one-to-one correspondence between the input and output values. However, it is common for the domain and codomain to be the same in order to fully capture the range of the function.

5. What is the significance of a bijective function in mathematics?

Bijective functions are important in mathematics because they allow for the mapping of one set of values to another in a unique and reversible way. This property makes them useful in a variety of mathematical fields, including calculus, algebra, and geometry.

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