Write two expressions equivalent to $sqrt -49$ . how can you do this?

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$sqrt -49$

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Answer 1 · 2018-04-03T00:47:52

$sqrt(-49)=sqrt49xxsqrt(-1)=+-7i$ i.e. $7i$ and $-7i$

Well if you need square root of a negative number, you have to move to the domain of complex numbers.

In complex number we use a number $i$ , which is defined so that $i^2=-1$ i.e. $sqrt(-1)=i$ .

Hence $sqrt(-49)=sqrt(49xx(-1))=sqrt49xxsqrt(-1)$

and as we can have both $7$ and $-7$ as $sqrt49$

$sqrt(-49)=sqrt49xxsqrt(-1)=+-7i$ i.e. $7i$ and $-7i$