Application of existence and uniqueness theorem

In summary: To apply the Existence and Uniqueness theorem, we need to check if $f$ is differentiable and if $\frac{\partial f}{\partial y}$ is continuous. In this case, $f$ is differentiable since it is a polynomial function. However, $\frac{\partial f}{\partial y}=12x^3y^2$ is not continuous at $x=0$ and $y=0$. Therefore, we cannot conclude anything about the existence and uniqueness of a solution to the given initial value problem.
  • #1
find_the_fun
148
0
Given the differential equation \(\displaystyle y'=4x^3y^3\) with initial condition \(\displaystyle y(1)=0\)determine what the existence and uniqueness theorem can conclude about the IVP.

I know the Existence and Uniquness theorem has two parts 1)check to see if the function is differentiable and 2)check to see if \(\displaystyle \frac{\partial f}{\partial y}\) is continious. If they both are true you can condlude there is only one solution (a unique solution). If not, then you can't conclude anything.

My problem is I don't understand which function I should be checking. Should I be checking the differential equation it self, or do I first need to solve and and then check the (a) solution?
 
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  • #2
find_the_fun said:
Given the differential equation \(\displaystyle y'=4x^3y^3\) with initial condition \(\displaystyle y(1)=0\)determine what the existence and uniqueness theorem can conclude about the IVP.

I know the Existence and Uniquness theorem has two parts 1)check to see if the function is differentiable and 2)check to see if \(\displaystyle \frac{\partial f}{\partial y}\) is continious. If they both are true you can condlude there is only one solution (a unique solution). If not, then you can't conclude anything.

My problem is I don't understand which function I should be checking. Should I be checking the differential equation it self, or do I first need to solve and and then check the (a) solution?

The initial value problem is of the form:

$$\left\{\begin{matrix}
y'=f(x,y)\\
\\
y(x_0)=y_0
\end{matrix}\right.$$

Therefore, the function $f$ is equal to $4x^3y^3$.
 

1. What is the existence and uniqueness theorem?

The existence and uniqueness theorem is a mathematical theorem that guarantees the existence of a unique solution to a specific type of problem. It is commonly used in differential equations and other areas of mathematics.

2. How is the existence and uniqueness theorem applied in science?

The existence and uniqueness theorem is commonly applied in science to prove the existence of a unique solution to a problem, such as in physics, engineering, and economics. It helps to ensure that solutions to problems are valid and accurate.

3. What are the conditions for the existence and uniqueness theorem to hold?

The existence and uniqueness theorem requires that the problem is well-posed, meaning that it has a unique solution and small changes in the initial conditions or parameters will result in small changes in the solution. It also requires that the problem is continuous and satisfies certain mathematical criteria.

4. Can the existence and uniqueness theorem be applied to all types of problems?

No, the existence and uniqueness theorem can only be applied to specific types of problems, such as initial value problems in differential equations. It cannot be applied to all mathematical problems.

5. Why is the existence and uniqueness theorem important in science?

The existence and uniqueness theorem is important in science because it provides a guarantee that a problem has a unique solution. This helps to ensure the accuracy and validity of scientific models and calculations, which are crucial for making accurate predictions and understanding the natural world.

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