Question

domain
$f(x) = \sqrt{1 - x}$

Answer 1

We have,
$f(x) = \sqrt{1 - x}$
We know, value in square root is always non-negative.
$= > 1 - x \geqslant 0 \: \\ = > 1 \geqslant x \\ = > x \leqslant 1$
Hence, Domain of f(x) is
$\infty < x \: \leqslant 1$