Math: Excel: square roots of negative numbers

Tutoring college math, complex numbers will likely arise. The tutor mentions using Excel.

Square roots of negative numbers (aka, complex numbers or imaginary numbers) may not be encountered by many high school students. However, in college math they are used, and electricians also use them.

Excel will calculate the square root of a negative number, using the imsqrt() function. Example:


gives, on this desktop, 1.8377E-16 + 3i.

1.8377E-16 is so tiny, of course, it’s equivalent to zero. So the effective answer is 3i, which is correct. An electrician might call it j3.


Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.

Tagged with: , ,

Leave a Reply