# How do you find the square root of a negative number, on a scientific calculator?

Apr 21, 2015

Usually you do it in the same way as for a positive number.

Here's how to do it on different brands of calculators.

SHARP

Press 2nd F, √.

The display shows $1.414 i$.

I use the fact that $\sqrt{- n} = \sqrt{n} i$ or, $i \sqrt{n}$.
Use the calculator's square root function to find the square root of the positive, then tack an $i$ onto the answer.
$\sqrt{26} = 5.099$ by calculator,
$\sqrt{- 26} = 5.099 i$