i
Imaginary unit, defined as i*i=1. A complex number is described as a + b*i, where a is the real part, and b is the imaginary part.
Try it yourself:
$1  i
 
$2  i * i
 
$3  sqrt(1)

Imaginary unit, defined as i*i=1. A complex number is described as a + b*i, where a is the real part, and b is the imaginary part.
Try it yourself:
$1  i
 
$2  i * i
 
$3  sqrt(1)
