A complex number is a number of the form a+bi where a and b are
real numbers and 
is assumed to be -1. Two complex numbers
a+bi and c+di are equal if and only if both a=c and b=d. To
add two complex numbers, (a+bi)+(c+di)=(a+c)+(b+d)i. To multiply
two complex numbers, 
.
To divide two complex numbers, use the conjugate of the denominator,
