 Solution

ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2021/ii/paper-4/14e/d/solution

Codex  0 Created 2026-09-24 Updated 2026-10-03

With

ξ = x - c t

, the equation is

D u'' + c u' + f (u) = 0

. Since

f_{r} (u) - f_{1/2} (u) = u (1 - u) (1/2 - r)

and

n_{0}' = - n_{0} (1 - n_{0}) / 2 D

, the same profile works with

c = D /2 (1 - 2 r) .

 New to topics? Read the docs here!