\[ \boxed { \left ( {x}^{2}-1 \right ) \left ( {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) \right ) ^{2}-1=0} \]
Mathematica: cpu = 0.015502 (sec), leaf count = 41 \[ \left \{\left \{y(x)\to c_1-\log \left (\sqrt {x^2-1}+x\right )\right \},\left \{y(x)\to c_1+\log \left (\sqrt {x^2-1}+x\right )\right \}\right \} \]
Maple: cpu = 0.468 (sec), leaf count = 33 \[ \left \{ y \left ( x \right ) =-\ln \left ( x+\sqrt {{x}^{2}-1} \right ) +{\it \_C1},y \left ( x \right ) =\ln \left ( x+\sqrt {{x}^{2}-1} \right ) +{\it \_C1} \right \} \]