Solution

ID: past-exam-of-the-differential-equations-1-course-of-the-university-of-oxford/2021/2/c/ii/solution

Continuous dependence of an ODE solution on parameters here means continuity of the map into with its supremum norm: for every and , all sufficiently close satisfy
Subtract the two integral equations and use the uniform Lipschitz constant on the rectangle. With we obtain
Part (i), with and , therefore proves, for ,
The case follows from uniqueness or the same estimate with zero forcing. If , the direct integral estimate gives . In either case the map is even Lipschitz continuous, and hence continuous, throughout in the stated supremum norm.

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