1. The problem statement, all variables and given/known data 13 equal charges are placed at the corners of a regular 13 sided polygon. What is the force on a test charge at the center? 2. Relevant equations Coulomb's law Principle of Superposition 3. The attempt at a solution Coulomb's law gives an answer of 0, but it is cumbersome. I am looking for a much more elegant solution, where I do not actually calculate the individual forces and add them up, but somehow realise that the forces will add up to zero based on the orientation of the charges.