True or false that all real function is an antiderivative

In summary, the conversation discusses the concept of antiderivatives and whether all functions have an antiderivative. The definition of an antiderivative is provided, and it is stated that not all functions have an antiderivative. Some examples are given, and it is clarified that every continuous function and every bounded function with a finite number of points of discontinuity have an antiderivative.
  • #1
kallazans
5
0
is it true or false that all real function is an antiderivative of some real function but neither real function have an antiderivative?

I still have the doubt!

Definition(Louis Leithold,The Calculus with Analytic Geometry)
Antiderivative: F is antiderivative of f in I if F'(x)=f(x) for all x in I.

The question is all f have some F in some I?
The question is all f is a G of some g in some I?
(Real Analysis)
 
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  • #2
By "primitive" do you mean that if [itex]f(x) = \int g(x) \, dx[/itex] then [itex]f(x)[/itex] is a primitive of [itex]g(x)[/itex]? (The usual English word for this is that [itex]f(x)[/itex] is an antiderivative or an integral of [itex]g(x)[/itex])


I'm not entirely sure what you're trying to ask... though it is false that any function is an antiderivative of another function.
 
  • #3
It's not clear what you mean by "either" function. If you mean the original function in the question and its anti-derivative, then obviously IF "every function had a anti-derivative", then it wouldn't make sense to say that THAT function did NOT have an anti-derivative.
However, as Hurkyl pointed out, it is not true that every function has a primitive (anti-derivative). For example, the function, f(x)= 1 if x is rational, 0 if x is irrational, does not have an antiderivative.
It IS true that every bounded function whose points of discontinuity form a set of measure 0 is integrable (has an anti-derivative). In particular every continuous function has an anti-derivative as well as every bounded function with only a finite number of points of discontinuity.
 

1. Is every real function an antiderivative?

No, not all real functions are antiderivatives. Only certain functions have an antiderivative, which is the inverse process of finding the derivative.

2. How can I determine if a function is an antiderivative?

To determine if a function is an antiderivative, you can use the Fundamental Theorem of Calculus. If the function can be expressed as the integral of another function, then it is an antiderivative.

3. Can a real function have multiple antiderivatives?

Yes, a real function can have multiple antiderivatives. This is because the indefinite integral of a function has a constant of integration, which can result in multiple antiderivatives.

4. Is the antiderivative of a function unique?

No, the antiderivative of a function is not always unique. As mentioned before, the indefinite integral has a constant of integration, which can result in multiple antiderivatives.

5. Are all antiderivatives continuous functions?

Yes, all antiderivatives are continuous functions. This is because the derivative of a function is defined as the limit of the difference quotient, which ensures the continuity of the function.

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