What is square root of 4
Submitted by tras rustamaji on Sun, 04/19/2015 - 11:45
It seems that after learning quadratic equation, some students confused about square root. They thought $\sqrt 4$ can be -2 or 2.
No! $\sqrt 4$ is $2$
But (you may say), $(-2)^2$ is also 4. Doesn't it mean -2 is also $\sqrt 4$
Nope! By convention squared root of a positive number is always a positive number.
But, if you are asked to find x that fit in this equation $x^2 = 4$ the answer $x = \pm \sqrt 4$.
See here, the value of x that fit to that equation is $x = -\sqrt 4$ or $x= +\sqrt 4$ and $\sqrt 4$ is 2.
Hence the solution for x is -2 or 2
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