Browse Questions

Domain of $f(x)=\large\frac{1}{\sqrt {|x|-x}}$ = ?

(A) $(-\infty,0)$
(B) $(-\infty,0]$
(C) $[1,\infty)$
(D) $[0,\infty)$
Can you answer this question?

Toolbox:
• $|x|=x,\:ifx\geq 0$ and $|x|=-x$ if $x<0$
$|x|-x>0$
$=0$ if $x>0\:x\:and\:=-2x\:\: if \:x <0$
but $|x|-x$ cannot be = 0.
$\therefore\:x<0$
Domain = $(-\infty,0)$
answered May 21, 2013