i^{2} = -1. (In electrical engineering and related fields, the imaginary unit is often written as j to avoid confusion with a changing current.) Every complex number can be written uniquely as a sum of a real number and an imaginary number. |

i^{2} = -1. (In electrical engineering and related fields, the imaginary unit is often written as j to avoid confusion with a changing current, traditionally denoted by i.) Every complex number can be written uniquely as a sum of a real number and an imaginary number. |