The IMSQRT function returns the square root of a complex number in x + yi or x + yj text format
Syntax:= IMSQRT(inumber)
The IMSQRT function syntax has the following arguments:
 Inumber: Required. A complex number for which you want the square root
Example: Let’s look at some Excel IMSQRT function examples and explore how to use the IMSQRT function as a worksheet function in Microsoft Excel:
Syntax: =IMSQRT(A2)
Result:
Based on the Excel spreadsheet above, the following IMSQRT examples would return:
Syntax: =IMSQRT(A3)
Result: 1+i
Syntax: =IMSQRT(A4)
Result: 2.899711522409771.55187851109421i
Syntax: =IMSQRT(A5)
Result: 1.611301089735750.310308236731844i
Syntax: =IMSQRT(A6)
Result: 2.12132034355964+0.707106781186548i
Syntax: =IMSQRT(A7)
Result: 3.46410161513775+3.46410161513775i
Syntax: =IMSQRT(A8)
Result: 1.09868411346781+0.455089860562227i
Syntax: =IMSQRT(A9)
Result: 2.2806933416653+1.09615788950152i
Syntax: =IMSQRT(A10)
Result: 3.043843301333171.80692613104986i
Syntax: =IMSQRT(A11)
Result: 32i
Syntax: =IMSQRT(A12)
Result: 4.022479320953552.48602893939289j
Syntax: =IMSQRT(A13)
Result: 5.30290204874601+2.26291187159259i
Note:
 Use COMPLEX to convert real and imaginary coefficients into a complex number.

The square root of a complex number is: where: and: and: