MATH 3FF3: Home assignment 3
Hello, dear friend, you can consult us at any time if you have any questions, add WeChat: daixieit
MATH 3FF3: Home assignment 3
1. Compute the Fourier transform fˆ(k) of the hat function
f (α) = {0(1) ,尸 3α3 1(1)
Use Parseval’s equality to obtain the exact value of
本 sin4 (夕)
4 d夕 .
_本 夕
2. Solve the advection–diffusion equation with dissipation:
0(尸)北北
by using the Fourier transform and write the solution in the convolution form.
3. Use the solution formula and find the explicit solution of the initial-value problem for the diffusion equation on the line:
北
Compute the asymptotic behavior of a(α, t) as t → +o for fixed α ∈ R.
4. Use the solution formula and find the explicit solution of the initial-value problem for the diffusion equation:
北
where x[_1,1] (α) = 1 for α ∈ [尸1, 1] and x[_1,1] (α) = 0 for 3α3 > 1. Confirm that a(α, t) 0 for every α ∈ R and t > 0.
5. Derive the heat kernel and the solution for the Neumann problem for the diffusion equation on the half-line:
, at = a北北 ,
. a北 (0, t) = 0,
. a(α, 0) = o(α),
α > 0,
α > 0,
t > 0,
t > 0,
by using the method of reflection, where o(α) : [0, o) → R is a given integrable, bounded, and continuous function. What is the value of a(0, t) for t = 0 and for t > 0?
2023-03-04