Showing That the Modified Bessel Function of the First Kind is a Solution

In summary, the conversation discusses the process of proving that the modified Bessel function, I_v(x), is a solution to the modified Bessel equation. The speaker has differentiated the MBF twice and plugged it in to show that the left hand side is equal to 0. After some work, they have obtained a left hand side with two terms inside a sum, multiplied by (x/2)^2k+v. There is some uncertainty about the validity of the result, as the second term is undefined when k=0. However, the speaker realizes they made a mistake in changing the index and ultimately obtained a series that converges to 0.
  • #1
womfalcs3
62
5
Hello,

I am in the process of showing that the modified Bessel function, I_v(x), is a solution to the modified Bessel equation,

x^2*y''+x*y'-(x^2+v^2)*y=0

I have differentiated the MBF twice and plugged it into show that the left hand side is in fact 0.

After a good amount of work, I've come to the following left hand side:

10shj0o.jpg


Where sigma=v.


Is that right? The math seems straight forward, and I only did one change of index that looks correct to me. I'm skeptical about the end result though.
 
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  • #2
Sorry, the actual left hand side I have are those two terms inside the sum multiplied by (x/2)^2k+v.

All inside the sum.
 
  • #3
womfalcs3 said:
Hello,


10shj0o.jpg


Is that right? The math seems straight forward, and I only did one change of index that looks correct to me. I'm skeptical about the end result though.

Not sure either. But the second term is undefined when k=0 , i.e. (-1)! = Γ(0) is undefined. Or do we assume the second term to be zero?
 
  • #4
matematikawan said:
Not sure either. But the second term is undefined when k=0 , i.e. (-1)! = Γ(0) is undefined. Or do we assume the second term to be zero?

Thank you for the response.

I just realized I made a mistake by changing the index, resulting in that denomintor. I eventually obtained a series that converged to 0.

Thank you again.
 

1. What is the Modified Bessel Function of the First Kind?

The Modified Bessel Function of the First Kind, denoted as I(x), is a special function in mathematics that is used to solve problems in engineering, physics, and other fields. It is a solution to the modified Bessel differential equation and is related to the regular Bessel function.

2. How is the Modified Bessel Function of the First Kind derived?

The Modified Bessel Function of the First Kind can be derived using the power series method or the integral representation method. The power series method involves expanding the function into a series of terms, while the integral representation method involves using a complex integral. Both methods result in the same function I(x).

3. What makes the Modified Bessel Function of the First Kind a solution?

The Modified Bessel Function of the First Kind is a solution because it satisfies the modified Bessel differential equation, which is a second-order linear differential equation. This means that when the function is plugged into the equation, it will result in a true statement.

4. What are the properties of the Modified Bessel Function of the First Kind?

The Modified Bessel Function of the First Kind has several important properties, including being an entire function, having an infinite number of roots, and having a singularity at the origin. It also has asymptotic behavior at large values of x and can be expressed in terms of other special functions.

5. How is the Modified Bessel Function of the First Kind used in real-world applications?

The Modified Bessel Function of the First Kind has many important applications in physics, engineering, and other fields. It is used to solve problems involving vibrations, heat transfer, and signal processing. It is also used in statistics and probability to model random processes. Additionally, it plays a crucial role in the study of elliptic integrals and elliptic functions.

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