Fundamental Theorem of Calc Problem using Chain Rule

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Homework Help Overview

The problem involves the application of the Fundamental Theorem of Calculus and the chain rule to evaluate the derivative of a function defined by an integral. The function is given as F(x) = (integral from 1 to x^3) (t^2 - 10)/(t + 1) dt.

Discussion Character

  • Mathematical reasoning, Problem interpretation, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to differentiate the integral using the chain rule, expressing the derivative in terms of x. Some participants question the steps taken, particularly regarding the treatment of the denominator during simplification.

Discussion Status

Participants are actively engaging in clarifying the steps involved in the differentiation process. There is a recognition of a mistake in the simplification, and guidance has been provided regarding the correct handling of the expression. The discussion reflects a collaborative effort to ensure understanding without reaching a final consensus.

Contextual Notes

The original poster is working within the constraints of a university assignment and is seeking clarification on their approach, particularly in relation to the syntax required for a Maple TA submission.

ManicPIxie
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Homework Statement


F(x) = (integral from 1 to x^3) (t^2 - 10)/(t + 1) dt
Evaluate F'(x)

Homework Equations


Using the chain rule

The Attempt at a Solution


Let u = x^3
Then:
[((x^3)^2 - 10) / (x^3 + 1)] ⋅ 3x^2
*step cancelling powers of x from fraction*
= (x^3 - 10)(3x^2)
= 3x^5 - 30x^2

I am trying to input a solution to a Maple TA problem for uni work, is this answer incorrect, or is possible that my maple TA syntax is incorrect.
My attempted answer on maple looked like:
(3*x^5) - (30*x^2)

Any help that *doesn't* just give me the answer is very much appreciated!
 
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ManicPIxie said:
[((x^3)^2 - 10) / (x^3 + 1)] ⋅ 3x^2
This is correct. But what happened to the denominator after this?
 
Last edited:
Shayan.J said:
This is correct. But what happened to the denominator after this?
In the cancelling step:
[(3x^6 - 10)/(x^3 + 1)] ⋅ 3x^2
It canceled to give:
(x^3 - 10) ⋅ 3x^2
 
ManicPIxie said:
In the cancelling step:
[(3x^6 - 10)/(x^3 + 1)] ⋅ 3x^2
It canceled to give:
(x^3 - 10) ⋅ 3x^2
You can't do that!
I don't even see how you're making that mistake to explain why its wrong!
 
Shayan.J said:
You can't do that!
I don't even see how you're making that mistake to explain why its wrong!
:/ Okay, my bad.

Retry:
[(x^6 - 10)/(x^3 + 1)] ⋅ 3x^2
= (3x^8 - 30x^2)/(x^3 + 1)
 
Aha! And entering that into Maple TA works!
Thanks for your help!
 

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