First time posting on Math SE, with kind of a basic algebra question.
Question
Does the relation:
$$\dfrac{(ab)^2}{|ab|} = \left|ab\right|$$
with $a,b \in \mathbb{R_{\ne 0}}$ always hold?
It seems trivial to me, but Wolfram Alpha gives me a strange answer because it specifies that this is True assuming $a,b$ are positive.
Reasoning
No matter what sign $a,b$ have, we have that $(ab)^2 > 0$ and $\left|ab\right| > 0$. Thus their ratio is greater than zero, and the magnitude of that ratio is exactly $ab$ with a positive sign, so $\left|ab\right|$.
Is what I said correct? If so, is this question a completely useless one? Sorry for the occasionally bad English!
Edit: formatted equations as suggested by Frentos
Your statement about Wolfram is not quite correct. It gives various alternate forms for this expression, two of which are:
$ab$ assuming $a$ and $b$ are positive
$ab\,sgn(a)\,sgn(b)$
(2) is equivalent to $|ab|$
See here