Derivative of Integral: Does the $x^2$ Cancel?

In summary, the Leibniz Integral Rule states that the derivative of an integral with variable limits is equal to the upper limit times the derivative of the upper limit, minus the lower limit times the derivative of the lower limit. In the given conversation, the participants discuss evaluating the derivative of a specific integral using this rule, with some confusion over the limits and function involved. Eventually, they arrive at the correct answer of -2x/(x^4+1).
  • #1
karush
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I assume the derivative cancels the intregal but the $x^2$ ?
 
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  • #2
The Leibniz Integral Rule states:

\(\displaystyle \frac{d}{dx}\int_{g(x)}^{h(x)}f(t)\,dt=f(h(x))h'(x)-f(g(x))g'(x)\)

Can you proceed?
 
  • #3
$h\left(x\right)=10h'\implies\left(x\right)=0$
$g\left(x\right)={x}^{2} \implies g'\left(x\right)=2x$
$f\left(z\right)=\frac{1}{{z}^{2}}+1$

I think that is $x^2$ it a fuzzy pic

I have to submit to preview the site freezes up if I preview on the edit page
 
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  • #4
The image is hard to read, but it appear to be that we are asked to evaluate:

\(\displaystyle \frac{d}{dx}\int_{x^3}^{10}\frac{dz}{z^2+1}\)

And if this is the case, then we have:

\(\displaystyle g(x)=x^3\implies g'(x)=3x^2\)

\(\displaystyle h(x)=10\implies h'(x)=0\)

\(\displaystyle f(z)=\frac{1}{z^2+1}\)
 
  • #5
The original pic looks like $x^2$

So I got
$\frac{2x}{{x}^{4}+1}$

I hope
 
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  • #6
If the lower limit is $x^2$, then we have:

\(\displaystyle \frac{d}{dx}\int_{x^2}^{10}\frac{dz}{z^2+1}=\frac{1}{10^2+1}\cdot0-\frac{1}{(x^2)^2+1}\cdot2x=-\frac{2x}{x^4+1}\)
 
  • #7
Cool, always learn a lot from MHB
 

Related to Derivative of Integral: Does the $x^2$ Cancel?

1. What is the derivative of an integral?

The derivative of an integral is the function that describes the rate of change of the original integral function at a given point. It represents the slope of the tangent line to the integral function at that point.

2. How do you find the derivative of an integral?

To find the derivative of an integral, you can use the Fundamental Theorem of Calculus, which states that the derivative of an integral is the original function being integrated. In other words, you can simply "undo" the integration by differentiating the function inside the integral sign.

3. When does the $x^2$ cancel in the derivative of an integral?

The $x^2$ term cancels in the derivative of an integral when the original function being integrated has a constant term, i.e. a term without any variables. This is because the derivative of a constant term is 0, so it disappears when differentiating the function inside the integral.

4. Why is it important to know when the $x^2$ cancels in the derivative of an integral?

Knowing when the $x^2$ term cancels in the derivative of an integral is important because it simplifies the process of finding the derivative. It allows us to use simpler derivative rules and can save time and effort in solving more complex integrals.

5. Are there any other terms that can cancel in the derivative of an integral?

Yes, there are other terms that can cancel in the derivative of an integral, such as constants or other terms without variables. It is important to carefully consider the function being integrated and its derivative before assuming any terms will cancel.

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