Jacobi Matrix and Multiple Intgrals

In summary, the question is asking for a function g: R^2 --> R that satisfies the given equation for all integrable functions h over the set D. The determinant for the Jacobian matrix of f(x,y) = (y^5,x^3) is -15y^4x^3, and the suggested change of variables is x=u^5 and y=v^3. The final result should have only u and v variables and can be obtained using the change of variables theorem.
  • #1
Kork
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Homework Statement



Let D be the set of points (x,y) in R^2 for which 0 is ≤ x ≤ 1 and 0 ≤ y ≤ 1. Find a function g: R^2 --> R for which:

∫_0^1 ∫_0^1 h(x,y)dxdy = ∫_0^1∫_0^1 h(y^5, x^3) * g(x,y)dxdy

is true for all functions h: D--> R integrable over D

In the question before this I was asked to find a jacobi matrix and determinant for f(x,y) = (y^5,x^3)

I found that the determinant is -15y^4x^3

Homework Equations




The Attempt at a Solution



∬_D f(x,y)dxdy= ∬_S g(v^5,u^3) * -15y^4x^2

Is this my final result? If not, can I get some help on how to go on?
 
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  • #2
Kork said:

Homework Statement



Let D be the set of points (x,y) in R^2 for which 0 is ≤ x ≤ 1 and 0 ≤ y ≤ 1. Find a function g: R^2 --> R for which:

∫_0^1 ∫_0^1 h(x,y)dxdy = ∫_0^1∫_0^1 h(y^5, x^3) * g(x,y)dxdy

is true for all functions h: D--> R integrable over D

In the question before this I was asked to find a jacobi matrix and determinant for f(x,y) = (y^5,x^3)

I found that the determinant is -15y^4x^3

Homework Equations




The Attempt at a Solution



∬_D f(x,y)dxdy= ∬_S g(v^5,u^3) * -15y^4x^2

Is this my final result? If not, can I get some help on how to go on?

Your answer shouldn't have 4 variables and needs the integration variables.

Your problem certainly suggests the change of variables ##x=u^5,\ y=v^3##. You need to check that maps the square to the square. Then use your change of variables theorem to express your integral in terms of ##u## and ##v##. Your result should have just ##u## and ##v## variables in it. Of course, they are dummy variables in the final result.
 

FAQ: Jacobi Matrix and Multiple Intgrals

What is a Jacobi Matrix?

A Jacobi Matrix, also known as a Jacobian matrix, is a square matrix of first-order partial derivatives. It is used to represent the gradient of a multivariate function, or the change in a vector-valued function with respect to its input variables.

What is the significance of the Jacobi Matrix?

The Jacobi Matrix is a powerful tool in multivariable calculus and vector analysis. It is used to calculate important properties such as determinants, eigenvalues, and eigenvectors. It is also an essential tool in the study of multiple integrals and their applications in various fields of science and engineering.

What is the relationship between Jacobi Matrix and multiple integrals?

The Jacobi Matrix is used to transform multiple integrals from one coordinate system to another. It is a key component in the change of variables formula, which allows for the evaluation of integrals in non-standard coordinate systems. The determinant of the Jacobi Matrix is also used to calculate the volume element in multiple integrals.

What are some common applications of Jacobi Matrix and multiple integrals?

The applications of Jacobi Matrix and multiple integrals are vast and diverse. They are used in physics, engineering, economics, and various other fields to solve problems involving multidimensional quantities, such as finding the center of mass, calculating work and line integrals, and solving differential equations.

How can I learn more about Jacobi Matrix and multiple integrals?

There are many great resources available to learn about Jacobi Matrix and multiple integrals. Some popular textbooks on the subject include "Vector Calculus" by Jerrold E. Marsden and Anthony J. Tromba, and "Multivariable Calculus" by James Stewart. Online resources such as Khan Academy and MIT OpenCourseWare also offer free courses and tutorials on the topic.

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