Find the derivative of an integral

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Homework Help Overview

The discussion revolves around finding the derivative of an integral, specifically the expression \(\frac{d}{dt}\int_{1}^{x} \sin t \, dt\). The subject area involves calculus, particularly the application of the Fundamental Theorem of Calculus.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants explore different methods for finding the derivative, including direct integration and application of the Fundamental Theorem of Calculus. Questions arise regarding the notation used and the variable with respect to which the derivative is taken.

Discussion Status

The discussion includes attempts to clarify the correct notation and method for differentiation. Some participants suggest remembering the Fundamental Theorem of Calculus, while others question the initial notation and its implications. There is no explicit consensus on the final result, but productive dialogue is occurring around the methods and interpretations.

Contextual Notes

Participants note potential confusion regarding the variable of differentiation and the dummy variable in the integral. There is acknowledgment of the need for clarity in notation to avoid misunderstandings.

IntegrateMe
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[tex]\frac {d} {dt}\int_{1}^{x} sint dt[/tex]
 
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This one is easy if you remember the First Fundamental Theorem of Calculus.
 
Thanks, i guess i was just looking for what particular method to use.
 
Well, there are two methods...

You could solve the integral, which isn't too hard (the answer is cos(1)-cos(x)), and then differentiate it wrt x to reveal the function. But it's easier to just remember the FTC.
 
The result is zero.
 
IntegrateMe said:
[tex]\frac {d} {dt}\int_{1}^{x} sint dt[/tex]

Are you sure that you notated this correctly? It looks unusual to me. The integration would be done with respect to a variable t (essentially a dummy variable), and the result will be a function of x (the upper limit). The derivative of this with respect to t would then be zero.

Did you intend the derivative to be with respect to x?
 
Yes, sorry, it's d/dx

Wouldn't the result be just "sinx" ?
 
IntegrateMe said:
Yes, sorry, it's d/dx

Wouldn't the result be just "sinx" ?
yes.
 
Thank you! :)
 

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