Finding the Derivative of an Integral with Limited Domain

In summary, this site says you must use an open interval and the function must be continuous for the technique to work, but this would not work in this case because sin is defined only from -1 to 1. You would then have to take the integral of the function and plug in the upper and lower limits.
  • #1
Justabeginner
309
1

Homework Statement


Find the derivative of the function:

[itex] f(x)= ∫e^sin(t) dt. [/itex] (A is cos (x) and B is (x^2))

Homework Equations


The Attempt at a Solution



I read this site http://mathmistakes.info/facts/CalculusFacts/learn/doi/doi.html and I was wondering how I would be able to determine what problems this technique would work for. It says it has to be an open interval, and the function must be continuous. But in this case, since sin is defined only from -1 to 1, this would not work right? Then what must I do in such a case? Do I take the integral of the function and then plug in the upper and lower limits? I am utterly confused. Thank you.
 
Last edited:
Physics news on Phys.org
  • #2
Justabeginner said:

Homework Statement


Find the derivative of the function:

[itex] f(x)= ∫e^sin(t) dt. [/itex] (A is cos (x) and B is (x^2))
You mean [itex]f(x)= \int e^{sin(t)}dt[/itex]. But what do "A" and "B" have to do with this?
And how does "x" come into it?

If you mean [itex]f(x)= \int_a^x e^{sin(t)} dt[/itex] then the derivative with respect to x is given by the "Fundamental Theorem of Calculus": The derivative, with respect to x, of [itex]\int_a^x F(t)dt[/itex] is F(x) no matter what a is.

Homework Equations


The Attempt at a Solution



I read this site http://mathmistakes.info/facts/CalculusFacts/learn/doi/doi.html and I was wondering how I would be able to determine what problems this technique would work for. It says it has to be an open interval, and the function must be continuous. But in this case, since sin is defined only from -1 to 1, this would not work right? Then what must I do in such a case? Do I take the integral of the function and then plug in the upper and lower limits? I am utterly confused. Thank you.
 
  • #3
A and B are the lower and upper limits of the integral but every time I put it in LaTex form it didn't pull up as I wanted it to, so I took it out. X is the variable used in the lower and upper limits of the integral.

So the integral limits are irrelevant to the problem itself, and by the Fundamental Theorem of Calculus, the derivative of ANY integral is F(x)?

Thank you.
 
  • #4
He means$$
f(x) = \int_{\cos x}^{x^2}e^{\sin t}\, dt$$
 
  • Like
Likes 1 person
  • #5
This will allow you to quickly apply the fundamental theorem :

$$\frac{d}{dx} \int_{a(x)}^{b(x)} f(t) dt = f(b(x))(b'(x)) - f(a(x))(a'(x))$$
 
  • #6
So in any question which asks me to find the derivative of an integral, this formula would be utilized?

[2x* e^ sin(x^2)] + [e^(sin(cos x)) * sin x] -Is this a correct application of the rule?

Thank you.
 
  • #7
Yes, the formula posted by Zondrina is generally applicable. Furthermore, you correctly applied it to your problem. Good work! :-)
 
  • #8
Thank you! :)
 

FAQ: Finding the Derivative of an Integral with Limited Domain

What is the derivative of an integral?

The derivative of an integral is a mathematical operation that shows how the output of a function changes as the input changes.

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 equal to the original function being integrated.

Why is the derivative of an integral important?

The derivative of an integral is important because it allows us to calculate the rate of change of a function at any given point. This is useful in many fields, including physics, economics, and engineering.

Can you explain the relationship between integrals and derivatives?

Integrals and derivatives are inverse operations of each other. This means that the derivative of an integral is the original function being integrated, and the integral of a derivative is the original function. They are both fundamental concepts in calculus and are used to solve a wide range of mathematical problems.

What are some real-world applications of the derivative of an integral?

The derivative of an integral has many real-world applications, including calculating velocity and acceleration in physics, determining marginal cost and revenue in economics, and finding the rate of change in biological processes. It is also used in optimization problems, such as finding the maximum or minimum value of a function.

Back
Top