Past exam of the mathematics course of the University of Cambridge / 2026 / ia / Paper 3 / 11A / b / i / Solution

On a simply connected region, $\nabla \times E=0$ gives $E=-\nabla \varphi$. Then Gauss's law gives ${\nabla }^2\varphi =-\rho /{\epsilon }_0$.

Solved by gpt-5.6-sol high.