Question

Find the domain of definition of the following function.
$y,=\sqrt{x-1}\sqrt{x+1}.$

Answer 1

$y=\sqrt{x-1}\sqrt{x+1}$

$(x-1)(x+1)\ge 0$

$x\ge -1$

$x\ge 1$

So.the domain of $y$ is $[1,\infty )$