Determine dynamics of stochastic differential equations (SDE)

In summary, the conversation discusses the use of Itô's lemma and the need for both a Riemann integral and an Itô integral in solving questions related to the dynamics of a function. The speaker also mentions using a Taylor expansion and infinite small values to solve the question.
  • #1
AxeO
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Hi guys, I´ve just started with SDE and Itô´s lemma but don't really know where and how to begin. I´ve realized that both a Reimann integral and Itô integral is needed both cannot figure out how to solve these questions. Would be much appreciated if someone would help me.

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  • #2
What exactly do you mean by 'determine the dynamics of'?

An elementary version of Ito's formula states that for $f \in C^2(\mathbb{R})$ and a semimartingale $X$, we have
$$f(X_t) =f(X_0) + \int_{0}^{t} f'(X_s)dX_s+\frac{1}{2}\int_{0}^{t}f''(X_s)d\langle X_s, X_s \rangle$$

So, can you be more clear about your troubles with this exercice?
 
  • #3
Sorry for being unclear, but what i meant was how to determine the diffusion of dV_t of the different functions. But I made an Taylor expansion and let \DeltaX and \Deltat be infinite small which gave me some multiplication rules which i could use to solve it (Itôs lemma). So I´ve already solved this question, thanks anyways for the help.
 

FAQ: Determine dynamics of stochastic differential equations (SDE)

1. What is the purpose of determining the dynamics of stochastic differential equations (SDE)?

The purpose of determining the dynamics of SDEs is to understand the behavior and evolution of complex systems that are subject to random fluctuations. This is particularly useful in fields such as finance, physics, and biology, where systems are often influenced by uncertain factors.

2. How are SDEs different from ordinary differential equations (ODEs)?

SDEs are different from ODEs in that they incorporate randomness or stochasticity in their formulation. This means that the evolution of the system is not entirely predictable, and its behavior can vary even when the initial conditions are the same. In contrast, ODEs are deterministic and have a unique solution for a given set of initial conditions.

3. What are the key components of an SDE?

The key components of an SDE are the deterministic drift term, which describes the expected behavior of the system, and the stochastic diffusion term, which accounts for the random fluctuations. These two components work together to determine the overall dynamics of the SDE.

4. How is the dynamics of an SDE determined?

The dynamics of an SDE are determined by solving the corresponding stochastic differential equation using advanced mathematical techniques such as numerical methods or analytical approximations. This involves simulating the system over many iterations to understand how it evolves over time and how it responds to different initial conditions and parameters.

5. What are some applications of SDEs?

SDEs have a wide range of applications in various fields, including finance, physics, biology, and engineering. In finance, SDEs are used to model stock prices, interest rates, and other financial variables. In physics, SDEs are used to study the behavior of particles in chaotic systems. In biology, SDEs are used to model population dynamics and the spread of diseases. In engineering, SDEs are used to analyze and design control systems that are subject to random disturbances.

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