Answer
$(-1-\sqrt 5,-1+\sqrt 5)$
Work Step by Step
The function requires that the radicand be larger than zero
$4-2x-x^2\gt0$ or $x^2+2x-4\lt0$
The zeros of the quadratic function can be found as $-1-\sqrt 5,-1+\sqrt 5$
The inequality happens when $x\in (-1-\sqrt 5,-1+\sqrt 5)$
