# i

## Purpose

Imaginary unit.

## Synopsis

    i
    a+bi
    x+i*y

## Description

As the basic complex unit `sqrt(-1)`,`i` is used to enter complex numbers. Since `i` is a function, it can be overridden and used as a variable, if desired. Thus, you can still use `i` as an index in `for` loops, etc.

The character `i` can also be used without a multiplication sign as a suffix in forming a complex numerical constant.

You can also use the character `j` as the complex unit.

## Examples

    Z = 2+3i
    Z = x+i*y
    Z = r*exp(i*theta)

## See Also

    conj, imag, j, real

(c) Copyright 1994 by The MathWorks, Inc.