Integral from 0 to 5: Solve "Variable 't' is not Defined" Error

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Homework Help Overview

The discussion revolves around evaluating the definite integral from 0 to 5 of the expression involving the variable 't' and the exponential function. Participants are addressing an error message related to the variable 't' not being defined in the context of the integral.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the integration by parts method and question whether the original integral was correctly stated. There is a suggestion that the integral might have been intended as $$\int_0^5 te^{-t}dt$$ instead of the original expression.

Discussion Status

The discussion is ongoing, with participants exploring different interpretations of the integral and identifying potential typos. Some guidance has been offered regarding the integration by parts process, and there is a focus on clarifying the correct form of the integral.

Contextual Notes

There is a noted confusion regarding the definition of the variable 't' in the context of the definite integral, as well as a suggestion to use the Preview button to avoid mistakes in posting.

mshiddensecret
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Homework Statement



Int from 0 to 5:

te^(-e)dt

Homework Equations

The Attempt at a Solution

I did the integration by parts and got:

(-t)e^(-1)-e^05+e^0

I got it incorrect: "Variable 't' is not defined in this context"
 
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mshiddensecret said:

Homework Statement



Int from 0 to 5:

te^(-e)dt

Homework Equations

The Attempt at a Solution

I did the integration by parts and got:

(-t)e^(-1)-e^05+e^0

I got it incorrect: "Variable 't' is not defined in this context"

Just to be clear, are you trying to evaluate:

$$\int_{0}^{5} t(e)^{-e}dt$$

because if you are, this is a very trivial integral.
 
mshiddensecret said:
"Variable 't' is not defined in this context"

That message means that there should be no variable t in the final answer. It's a definite integral.
 
mshiddensecret said:

Homework Statement



Int from 0 to 5:

te^(-e)dt
Is the above a typo?
Could this be your integral?
$$\int_0^5 te^{-t}dt$$
 
Mark44 said:
Is the above a typo?
Could this be your integral?
$$\int_0^5 te^{-t}dt$$
Yeah. That's what it looks like.
 
@mshiddensecret, try to be more careful when you post. SteamKing and Dick were unable to help you because of this mistake.
 
Just a suggestion: Use the Preview button to check your posts before submission. It's helped me avoid more than a few mistakes.
 
Mark44 said:
Is the above a typo?
Could this be your integral?
$$\int_0^5 te^{-t}dt$$
mshiddensecret said:
Yeah. That's what it looks like.
Show us the work you did in integrating by parts...
 
I agree with Mark44, it seems like you went wrong somewhere in the integration by parts.
## \int_a^b u dv = \left. uv \right|_a^b - \int_a^b v du ##
The first term in your answer above looks like you may have misinterpreted ##\left. uv \right|_a^b##
Did you use ## u = t, \, dv = e^{-t}dt##?
 

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