How to get value of x and y here?

Question

$x^2=16$
$y =\sqrt{16}$

here I know that when we solve value of $x$ then we get two values $+4$ and $-4$
But why we don't' get two values of $y$. Can you please explain this. Thanks for help.

The principal square root function $f(x) = \sqrt{x}$ is a function that maps the set of non-negative real numbers onto itself. So it is only possible to take square roots of positive numbers. To take a square root of a negative number, you first have to go to complex domain, where you're left with an imaginary part and a real part, of which you can then take a square root of. — Hasan, Oct 20 '13 at 11:50

score 1 · Accepted Answer · answered Oct 20 '13 at 11:41

1

This is not an inequality but a system of equations, there are two numbers that squared will give 16, -4 and 4. By definition the square root function gives only one value ( by definition ), that is why $y=4$.

PS : repeating by definition is on purpose.

answered Oct 20 '13 at 11:41

jimjim

9,675

So according to you square root function can't be negative number ....that's why we y =4 not -4 ? – Android developer Oct 20 '13 at 11:46
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@Androiddeveloper : yes, by definition of square root function. – jimjim Oct 20 '13 at 11:47

How to get value of x and y here?

1 Answers1