Can you take the inverse of any function?

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Discussion Overview

The discussion centers around the concept of taking the inverse of functions, particularly in the context of integrals. Participants explore the conditions under which inverses can be applied and question the validity of manipulating integrals in this manner.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant suggests that inverses can be applied to limits, questioning if the same applies to integrals.
  • Another participant notes that not every function has an inverse and emphasizes that the inverse of an integral is generally not the integral of the inverse of the function.
  • A participant proposes a specific example using the function y=2x+1 and asks if the integral can be manipulated to involve the inverse function.
  • There is a reiteration of the previous example, with a challenge to integrate and see the results, suggesting that the outcome will not relate to the inverse of the original function.
  • One participant provocatively claims that you can take the inverse of any function, but clarifies that the inverse may not always yield a unique function, using the sine function as an example.

Areas of Agreement / Disagreement

Participants express differing views on the applicability of taking inverses in the context of integrals, with no consensus reached on the validity of the proposed manipulations.

Contextual Notes

Participants highlight limitations regarding the uniqueness of inverses and the conditions under which functions have inverses, but these aspects remain unresolved.

ZeroPivot
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i know when you are dealing with limits you can take the inverse to fit the standard limit equations.

how about integrals? can u take the inverse for instance: integral(f(x)dx)

turn it into integral((1/f(x))dx)^-1) get the answer and then reverse it back?

when can u or can't you take the inverse?
 
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First, not every function has an inverse. But if a function has an inverse, then, theoretically, you can find it. Exactly how you would find that inverse and how hard it would be depends on the function.

Do you have some specific reason for asking about the inverse of an integral? In general the inverse of the integral of a function is NOT the integral of the inverse of the function. Your last expression has an unmatched right parenthesis so it is hard to tell exactly what you intend.
 
lets say the fuction is continuous and has an inverse.

something easy say y=2x+1 and u want the integral integral(2x+1)dx can u switch it around and say (integral(1/(2x+1))dx)^-1, are there any integrals u can do this to or is it a no no?
 
ZeroPivot said:
lets say the fuction is continuous and has an inverse.

something easy say y=2x+1 and u want the integral integral(2x+1)dx can u switch it around and say (integral(1/(2x+1))dx)^-1, are there any integrals u can do this to or is it a no no?

Integrate that and see what you get. It'll have nothing to do with the inverse of y = 2x+1.
 
ZeroPivot said:
i know when you are dealing with limits you can take the inverse to fit the standard limit equations.

how about integrals? can u take the inverse for instance: integral(f(x)dx)

turn it into integral((1/f(x))dx)^-1) get the answer and then reverse it back?

when can u or can't you take the inverse?
You can take the inverse of any function. (pause for shock value :-p)

HOWEVER, it is important to note that the inverse of a function is not necessarily a function. For example, consider the ##\sin## function. Since ##\sin(x)=\sin(x+2\pi)##, ##\sin^{-1}(\sin(x))## will not be unique. In fact, ##\sin^{-1}(\sin(x))=x+2\pi n##, where ##n\in\mathbb{Z}##.
 

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