A relation which intercepts with....

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Discussion Overview

The discussion revolves around the possibility of a mathematical relation intersecting with both its derivative and indefinite integral at the same point, excluding the exponential function e^x. Participants explore various functions that meet this criterion, focusing on the conditions under which such intersections occur.

Discussion Character

  • Exploratory
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant proposes defining a function f(x) such that the solutions to f(x) = f'(x) and f(x) = ∫f(x)dx coincide, excluding e^x and assuming the constant of integration is zero.
  • Another participant notes that the equation f(x) = f'(x) is a defining characteristic of e^x, prompting a request for clarification on the original inquiry.
  • A participant provides an example using f(x) = sin^4(x), which intersects with its derivative and integral at the origin, suggesting a search for other functions with similar intersections, preferably not at the origin.
  • One suggestion for a function is f(x) = (x-a)^n, with n > 1, which is acknowledged as a suitable example by another participant.

Areas of Agreement / Disagreement

Participants express varying viewpoints on the types of functions that can exhibit the desired intersections, with some examples provided but no consensus on a definitive list of such functions.

Contextual Notes

The discussion does not resolve the broader question of which functions may exhibit the three-way intersection, and assumptions about the nature of the functions are not fully explored.

Who May Find This Useful

Mathematicians, students, and enthusiasts interested in the properties of functions, derivatives, and integrals, particularly in the context of intersections and relationships between these mathematical entities.

Saracen Rue
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I am wondering if it's possible for a relation to intercept with both it's derivative and indefinite integral at the same location (not including e^x as it shares the same rule as both it's integral and derivative). This is also assuming the constant of the indefinite integral is equal to zero.

Basically;
Define f(x) where the solution to f(x) = f'(x) is the same as the solution to f(x) = ∫f(x)dx, f(x) ≠ e^x and c = 0
 
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##f(x) = f '(x)## is basically one way (among many) to define ##e^x## (up to a constant or the requirement##f(0)=1##).
What exactly are you looking for?
 
fresh_42 said:
##f(x) = f '(x)## is basically one way (among many) to define ##e^x## (up to a constant or the requirement##f(0)=1##).
What exactly are you looking for?
I'll give an example;
Let f(x) = sin^4(x). In this scenario, f(x), f'(x) and ∫f(x)dx all intersect the x-axis at (0, 0). Therefore, there is a three-way intersection between f(x), f'(x) and ∫f(x)dx at said point. I'm looking for other functions or relations which also have a three-way intersection between f(x), f'(x) and ∫f(x)dx. Preferably not at the origin, but I don't mind if they are.
 
How about ##f(x)=(x-a)^n## with ##n > 1##?
 
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fresh_42 said:
How about ##f(x)=(x-a)^n## with ##n > 1##?
Yes, that is an excellent example of what I meant. Thank you :)
 

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