How to make functions right-continuous

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Homework Help Overview

The discussion revolves around the problem of redefining a vector function r(t) to ensure it is right-continuous at t=0. The function is composed of three components, each involving limits and potential indeterminate forms.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • Participants explore the concept of right continuity and question how to define the function at t=0. There is discussion about ensuring the limit as t approaches 0 from the right matches the defined value at t=0. Some participants suggest specific values for the components of the function.

Discussion Status

The conversation is active, with participants providing suggestions for the values of the components at t=0 and discussing the implications of indeterminate forms. There is acknowledgment of the need for continuity and the use of L'Hopital's Rule to evaluate limits.

Contextual Notes

Participants are navigating the definitions and limits of the component functions, particularly focusing on the behavior of the function as t approaches 0. The discussion includes the challenge of handling indeterminate forms in the context of the problem.

Sho Kano
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Homework Statement


Given r(t)=\left< \frac { sint }{ t } ,\frac { { e }^{ 2t }-1 }{ t } ,{ t }^{ 2 }ln(t) \right>
Re-define r(t) to make it right continuous at t=0

Homework Equations

The Attempt at a Solution


This is probably the simplest problem ever, but I don't even know what it's asking for. Right continuous as in right handed limit? How can I re-define it?
 
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Sho Kano said:

Homework Statement


Given r(t)=\left< \frac { sint }{ t } ,\frac { { e }^{ 2t }-1 }{ t } ,{ t }^{ 2 }ln(t) \right>
Re-define r(t) to make it right continuous at t=0

Homework Equations

The Attempt at a Solution


This is probably the simplest problem ever, but I don't even know what it's asking for. Right continuous as in right handed limit? How can I re-define it?
You need to define values for each of the three component functions so that r(0) exists, and ##\lim_{t \to 0^+} r(t)## exists and is equal to r(0).
 
Mark44 said:
You need to define values for each of the three component functions so that r(0) exists, and ##\lim_{t \to 0^+} r(t)## exists and is equal to r(0).
So something like
x=1 when t=0
y=2 when t=0
 
Sho Kano said:
So something like
x=1 when t=0
y=2 when t=0
Correct.

How about z when t = 0 ?
 
SammyS said:
Correct.

How about z when t = 0 ?
z = 0 when t = 0 because 0*∞ is indeterminate if the 0 is not "constant"?
 
Sho Kano said:
z = 0 when t = 0 because 0*∞ is indeterminate if the 0 is not "constant"?
"Indeterminate" means you can't say what the value will be.
If you write ##t^2\ln(t)## as ##\frac{\ln(t)}{t^{-2}}##, you now have the indeterminate form ##[\frac{\infty}{\infty}]##, so you can use L'Hopital's Rule on it.
 
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Mark44 said:
"Indeterminate" means you can't say what the value will be.
If you write ##t^2\ln(t)## as ##\frac{\ln(t)}{t^{-2}}##, you now have the indeterminate form ##[\frac{\infty}{\infty}]##, so you can use L'Hopital's Rule on it.
The limit is 0, by L'Hopital's Rule. So the way I'm re-defining it is making r(t) continuous for t is not 0, and make r(0)=<1,2,0>, like a piece-wise function
 
Sho Kano said:
The limit is 0, by L'Hopital's Rule. So the way I'm re-defining it is making r(t) continuous for t is not 0, and make r(0)=<1,2,0>, like a piece-wise function
Yes
 

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