The COMPLEX function converts real and imaginary coefficients into a complex number of the form x + yi or x + yj.
Syntax
=COMPLEX(real_num,i_num,[suffix])
Arguments
Argument  Description  

real_num  The real coefficient of the complex number  
i_num  The imaginary coefficient of the complex number  
[suffix]  Optional. The suffix for the imaginary component of the complex number

Examples
A  B  C  

1  Formula  Result  Notes 
2  =COMPLEX(3,4)  3+4i  Complex number with 3 and 4 as the real and imaginary coefficients 
3  =COMPLEX(3,4,”j”)  3+4j  Complex number with 3 and 4 as the real and imaginary coefficients, and j as the [suffix] 
4  =COMPLEX(0,1)  i  Complex number with 0 and 1 as the real and imaginary coefficients 
5  =COMPLEX(1,0)  1  Complex number with 1 and 0 as the real and imaginary coefficients 
Common Function Error(s)
Problem  What went wrong  

#VALUE!  Occurs if either:


#NAME?  Occurs when Analysis ToolPak addin is not enabled 
Within the real number scale, there is no such thing as the square root of a negative number. However, within the world of complex numbers, the ‘imaginary’ value, i is used to represent the square root of 1.
Therefore, the square root of any negative number can be represented by the square root of the number’s modulus, multiplied by i.
For example:
A Complex Number is composed of a real number combined with an imaginary number, e.g. the complex number, z, is written as: