Convolution of a Gaussian with itself from the definition

In summary, the convolution of g(x) = e^{-πx^{2}} with itself from -∞ to ∞ is equal to -2π(y-x/2)^2-πx^2/2 after completing the square. The attempt to solve using integration by parts leads to the conclusion that the convolution is 0, but completing the square can help solve the problem.
  • #1
GuiltySparks
11
0

Homework Statement



Find the convolution of g(x) = [itex]e^{-πx^{2}}[/itex] with itself from -∞ to ∞ using the definition of convolution, not the Fourier Transform.



The Attempt at a Solution



See my attachment. My professor said that you have to use integration by parts, but I keep getting stuck. No matter what I do, I reach the conclusion that the convolution is 0. Is there something that I'm missing here?
 

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  • #2
GuiltySparks said:

Homework Statement



Find the convolution of g(x) = [itex]e^{-πx^{2}}[/itex] with itself from -∞ to ∞ using the definition of convolution, not the Fourier Transform.

The Attempt at a Solution



See my attachment. My professor said that you have to use integration by parts, but I keep getting stuck. No matter what I do, I reach the conclusion that the convolution is 0. Is there something that I'm missing here?

Complete the square.

[itex]\displaystyle -2\pi\left( y^2-xy\right)-\pi x^2 [/itex]
[itex]\displaystyle =
-2\pi\left( y^2-xy+\frac{x^2}{4}-\frac{x^2}{4}\right)-\pi x^2 [/itex]

[itex]\displaystyle =-2\pi\left( y-\frac{x}{2}\right)^2+2\pi\frac{x^2}{4}-\pi x^2 [/itex]

[itex]\displaystyle =-2\pi\left( y-\frac{x}{2}\right)^2-\pi\frac{x^2}{2} [/itex]​
 

1. What is the definition of convolution of a Gaussian with itself?

The convolution of a Gaussian with itself is a mathematical operation that combines two functions to produce a third function. In this case, it involves taking a Gaussian function and convolving it with itself, resulting in a new Gaussian function.

2. How is the convolution of a Gaussian with itself calculated?

The convolution of a Gaussian with itself is calculated using the convolution integral, which involves multiplying the two functions together and then integrating over all possible values of the variable. In simpler terms, it is a process of "sliding" one function over the other and calculating the overlap at each point.

3. What is the significance of convolving a Gaussian with itself?

Convolving a Gaussian with itself is a common mathematical operation that has many practical applications. It can be used to smooth data, remove noise, and estimate the probability distribution of a system. It is also used in signal processing, image processing, and machine learning algorithms.

4. How does the convolution of a Gaussian with itself affect the shape of the Gaussian?

The convolution of a Gaussian with itself results in a new Gaussian function that is wider and smoother compared to the original Gaussian. This is because the convolution "blurs" the function, spreading out the peak and reducing the amplitude, resulting in a wider and flatter curve.

5. Can the convolution of a Gaussian with itself be represented algebraically?

Yes, the convolution of a Gaussian with itself can be represented algebraically using the convolution theorem. This theorem states that the convolution of two functions in the time domain is equivalent to the multiplication of their Fourier transforms in the frequency domain. This allows for a more efficient and concise way of calculating the convolution.

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