Root of 4 is just 2 or (-2 and 2)?

[user12217]

Initially, as a part of our PrepSwift course, we were taught that we should only consider the positive roots. When we are considering the root of four, we should just consider 2. This question, along with some of the other questions which come under the quant exercises, consider both the positive and negative roots.

[Kweku]

Hi @user12217

Refer to below link

Cylverixxx expertly explains it.

Quant: Query regarding when to consider both +ve and -ve solutions and when only +ve

\sqrt{.} refers to the principal square root. Every nonnegative number x has a unique (only one) nonnegative square root. So, whenever you see something like \sqrt{9}, you’re really being asked about the principal square root, which is just 3 (it’s the only nonnegative number that, when squared, gives you 9; a number like -3 is negative so it falls outside this definition). You can extrapolate this “rule” for all even roots. For something like y^2= 64 The natural way to solve it is to apply…

[user12217]

Thank you so much!