Help with Changing of variables, Jacobian, Double Integrals?

Click For Summary
The discussion revolves around transforming the variables using the mapping T(u,v) = (u² - v², 2uv) to evaluate a double integral over a specified triangular region. The Jacobian for the transformation is calculated as 4u² + 4v². The integral to be evaluated is ∫∫ sqrt((u² - v²)² + (2uv)²) (4u² + 4v²) dudv. The user seeks assistance in determining the correct bounds for the integrals in terms of u and v, noting that the initial bounds for u and v are 0 ≤ u ≤ 4 and 0 ≤ v ≤ 4. The discussion highlights the need for clarification on the integration limits based on the transformed variables.
Suy
Messages
101
Reaction score
0

Homework Statement



Show that T(u,v) = (u2 - v2, 2uv)
maps to the triangle = {(u,v): 0 ≤ v ≤ u ≤ 4} to the domain D
bounded by x=0, y=0, and y2 = 1024 - 64x.

Use T to evaluate ∬D sqrt(x2+y2) dxdy

Homework Equations



The Attempt at a Solution



x=u2-v2
y=2uv
Jacobian= 4u2+4v2 dudv
I guess the equation in the changed variable integral should be ∫∫sqrt((u2-v2)2+(2uv)2) (4u2+4v2) dudv

But, I don't know how to get the bounds for the integrals in terms of u and v.
Can someone help me on this??
 
Physics news on Phys.org
The first part of the problem already told you what the bounds of u and v are
 
I know that 0 ≤ u ≤ 4 and 0 ≤ v ≤4.
For y^2 = 1024 - 64x, x is restricted from 0 ≤ x ≤16 and 0 ≤ y ≤32??
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

Similar threads

Replies
21
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 16 ·
Replies
16
Views
2K
Replies
2
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
7K
  • · Replies 21 ·
Replies
21
Views
2K
Replies
5
Views
2K
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
1K