Math Basics

All About Numbers

What are complex numbers?

Complex numbers have two parts: the “real” part (any real number) and an “imaginary” part (any number with an i in it). The standard complex number format is “a + bi,” or a real number plus an imaginary number. It is also often seen as x + iy, because while real numbers are viewed on a line, complex numbers are viewed graphically on an Argand (or polar) coordinate system: The imaginary numbers make up the vertical (or y) axis as iy, while the horizontal (or x) axis is occupied by real numbers. (For more information about coordinate systems, see “Geometry and Trigonometry.”)


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