Abstract
The coordinates, introduced by Descartes to represent geometrical figures by algebraic equations, are complex quantities corresponding to the solutions of the algebraic equations; on the other hand we have used real coordinates in physics by reason that only the real ones have physical meaning. This reason is, however, nothing but an empirical one and has no ground in actual facts. The coordinates should be complex also in physics in accordance with their original significance when we can give them physical meaning. In the present paper we give physical meaning to the complex coordinates and remove the difficulties of the radiation theory by using them