How to make functions right-continuous

In summary, to make r(t) right continuous at t=0, we need to define values for x, y, and z such that r(0) exists and the limit of r(t) as t approaches 0 from the right is equal to r(0). Using L'Hopital's Rule, we can determine that the limit of t^2*ln(t) as t approaches 0 is 0. Therefore, we can define r(0) as <1,2,0>, making r(t) a piece-wise function that is continuous at t=0.
  • #1
Sho Kano
372
3

Homework Statement


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

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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  • #2
Sho Kano said:

Homework Statement


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

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).
 
  • #3
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
 
  • #4
Sho Kano said:
So something like
x=1 when t=0
y=2 when t=0
Correct.

How about z when t = 0 ?
 
  • #5
SammyS said:
Correct.

How about z when t = 0 ?
z = 0 when t = 0 because 0*∞ is indeterminate if the 0 is not "constant"?
 
  • #6
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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  • #7
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
 
  • #8
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
 

Related to How to make functions right-continuous

1. What does it mean for a function to be right-continuous?

Right-continuous means that as the input to a function increases, the output also increases, or stays the same. In other words, there are no sudden jumps or discontinuities in the function's graph from left to right.

2. How can I make my function right-continuous?

To make a function right-continuous, you simply need to ensure that there are no sudden jumps or gaps in the function's graph. This can be achieved by using a piecewise function, where different equations are used for different intervals of the input, or by using a limit to smooth out any potential discontinuities.

3. Why is it important for a function to be right-continuous?

Having a right-continuous function is important for ensuring that the function is well-defined and behaves consistently. It also allows for easier analysis and calculation of properties such as derivatives and integrals.

4. Can a function be both left-continuous and right-continuous?

Yes, a function can be both left-continuous and right-continuous. This means that as the input decreases from right to left, the output also decreases or stays the same. A function that is both left-continuous and right-continuous is known as a continuous function.

5. Are there any real-world applications for right-continuous functions?

Yes, there are many real-world applications for right-continuous functions. For example, in economics, the demand and supply curves are often assumed to be right-continuous, as a change in price will result in a change in quantity demanded or supplied, but not a sudden jump. In finance, right-continuous functions are used to model the continuous compounding of interest. They are also commonly used in probability and statistics to model continuous random variables.

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