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

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Answer 1 · 2015-04-21T15:47:40

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, √.

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The display shows $1.414i$ .

Would others please add the instructions for their brand of calculator?

Answer 2 · 2015-04-21T16:05:49

I use the fact that $sqrt(-n) = sqrtn i$ or, $isqrtn$ .

Use the calculator's square root function to find the square root of the positive, then tack an $i$ onto the answer.

$sqrt26 = 5.099$ by calculator,
so

$sqrt(-26) = 5.099i$