Question 198
The non-null real numbers $a$ and $b$ check the equality $$
\frac{a^{2} b^{2}}{a^{4}-2 b^{4}}=1
$$ Find, reasonably, all the values taken by the expression $$
\frac{a^{2}-b^{2}}{a^{2}+b^{2}}
$$
\frac{a^{2} b^{2}}{a^{4}-2 b^{4}}=1
$$ Find, reasonably, all the values taken by the expression $$
\frac{a^{2}-b^{2}}{a^{2}+b^{2}}
$$