How can I make a JavaScript code that can find square roots of negative numbers?

Answer 1

you need to have the knowledge of comex number in math, that should help

Answer 2

Complex/Imaginary numbers:
https://en.m.wikipedia.org/wiki/Imaginary_number
https://en.m.wikipedia.org/wiki/Complex_number

Some math resources:
https://www.sololearn.com/Discuss/713822/?ref=app