Proving the graph of an inverse function

In summary, we have shown that the set Γ′ is the graph of f−1, by proving that the first projection of Γ′ is a bijection.
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The1TL
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Homework Statement


Let f:A→B be a bijection and let f-1 :B→Aitsinverse. If Γ ⊂ A×B is the graph of f, show that the set, Γ′ ⊂ B×A defined as Γ′ = {(b, a)|(a, b) ∈ Γ} is the graph of f−1.

Homework Equations





The Attempt at a Solution


So far i have proved that the second projection of gamma must be a bijection. I know that i need to somehow show that the first projection of gamma prime is a bijection, but I am not sure how to do that.
 
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To show that the first projection of Γ′ is a bijection, we need to prove that it is both injective and surjective.

Injective: Let (b1, a1) and (b2, a2) be two points in Γ′ such that b1 ≠ b2. This means that (a1, b1) and (a2, b2) are two points in Γ. Since f is a bijection, (a1, b1) and (a2, b2) must map to unique points in B. Therefore, a1 ≠ a2. This shows that the first projection of Γ′ is injective.

Surjective: Let (b, a) be any point in B×A. Since Γ is the graph of f, there exists an element (a, b) in Γ. This means that (b, a) is also in Γ′. Therefore, the first projection of Γ′ is surjective.

Since the first projection of Γ′ is both injective and surjective, it is a bijection. This shows that Γ′ is the graph of f−1.
 

1. How do you prove that a function is the inverse of another function?

In order to prove that a function is the inverse of another function, you can use the horizontal line test. If a horizontal line intersects the graph of the function at only one point, and the inverse function also passes through that point, then the functions are inverses of each other.

2. Can you prove the graph of an inverse function algebraically?

Yes, there are multiple algebraic methods for proving that a function is the inverse of another function. One common method is to use the composition of functions. If the composition of a function with its inverse results in the identity function, then the functions are inverses of each other.

3. How do you prove that a function is its own inverse?

A function is its own inverse if the composition of the function with itself results in the identity function. In other words, if f(x) = x, then f(f(x)) = x. You can also use the symmetry property of the graph of an inverse function to prove this.

4. Can two functions have more than one inverse?

No, a function can only have one inverse. This is because a function must pass the vertical line test, meaning that for each input, there can only be one output. If a function has multiple inverses, then it would fail the vertical line test.

5. Is it possible for a function to have an inverse that is not a function?

No, a function must have a unique output for every input. If a function has an inverse that is not a function, it would mean that there are multiple outputs for a single input, which goes against the definition of a function. Therefore, a function must have an inverse that is also a function.

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