Determining Existence and Uniqueness

Click For Summary
The discussion focuses on determining the existence and uniqueness of solutions for the initial value problem dy/dx = y^(1/3) with the condition y(0) = 0. The Existence and Uniqueness of Solutions Theorem is referenced, which states that if the function and its partial derivative are continuous in a region containing the initial point, then a unique solution exists. In this case, the function y^(1/3) is continuous, but its partial derivative is not continuous at y = 0, leading to questions about uniqueness. Participants are encouraged to explore the implications of the theorem and consider potential solutions. The conclusion emphasizes the need for careful analysis of the conditions for applying the theorem to this specific problem.
Ian Baughman
Messages
36
Reaction score
2
Member warned that an effort must be shown

Homework Statement



Determine whether existence of at least one solution of the given initial value problem is guaranteed and, if so, whether uniqueness of the solution is guaranteed.

dy/dx=y^(1/3); y(0)=0

Homework Equations



Existence and Uniqueness of Solutions Theorem:

Suppose that both the function ƒ(x,y) and its partial derivative [D][/y]f(x,y) are continuous on some rectangle R in the xy-plane that contains the point (a,b) in its interior. Then, for some open interval I containing the point a, the initial value problem

dy/dx=ƒ(x,y), y(a)=b

has one and only one solution that is defined on the interval I.

The Attempt at a Solution

 
Last edited:
Physics news on Phys.org
Ian Baughman said:

Homework Statement



Determine whether existence of at least one solution of the given initial value problem is guaranteed and, if so, whether uniqueness of the solution is guaranteed.

dy/dx=y^(1/3); y(0)=0

Homework Equations



Existence and Uniqueness of Solutions Theorem:

Suppose that both the function ƒ(x,y) and its partial derivative [D][/y]f(x,y) are continuous on some rectangle R in the xy-plane that contains the point (a,b) in its interior. Then, for some open interval I containing the point a, the initial value problem

dy/dx=ƒ(x,y), y(a)=b

has one and only one solution that is defined on the interval I.

The Attempt at a Solution


So, what have you tried? You have to show some effort in this forum. Does the theorem apply to your problem? Have you looked for solution(s)? Show us what you are thinking...
 
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 6 ·
Replies
6
Views
2K
Replies
2
Views
1K
Replies
3
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 20 ·
Replies
20
Views
1K
Replies
3
Views
2K
  • · Replies 8 ·
Replies
8
Views
1K
  • · Replies 18 ·
Replies
18
Views
2K
Replies
20
Views
3K
  • · Replies 4 ·
Replies
4
Views
1K