Solution

ID: past-exam-of-the-short-options-course-of-the-university-of-oxford/2021/4/a/i/solution

Take and
Its Jacobian matrix and determinant are
Thus its total derivative is invertible everywhere, and the inverse function theorem makes it locally invertible. But , so it is not injective and has no global inverse on its image. The domain is open and connected as required.

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