Find the values of x for which expression $\sqrt{1-\sqrt{1-\sqrt{1-x^2}}}$ is meaningful.
Answer & explanation
Correct answer: option 1
$\sqrt{1-\sqrt{1-\sqrt{1-x^2}}}$ is meaningful if
$1-\sqrt{1-\sqrt{1-x^2}}≥0$
or $\sqrt{1-\sqrt{1-x^2}}≤1$
or $1-\sqrt{1-x^2}≤1$
or $\sqrt{1-x^2}≥0$
or $1-x^2≥0$
or $x^2≤1$ or $x∈[-1, 1]$