\[ \boxed { {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) -{\frac {\sqrt { \left ( y \left ( x \right ) \right ) ^{2}-1}}{\sqrt {{x}^{2}-1}}}=0} \]
Mathematica: cpu = 0.049506 (sec), leaf count = 55 \[ \left \{\left \{y(x)\to \frac {1}{2} \left (-e^{-c_1} \sqrt {x^2-1}+e^{c_1} \sqrt {x^2-1}+e^{-c_1} x+e^{c_1} x\right )\right \}\right \} \]
Maple: cpu = 0.016 (sec), leaf count = 29 \[ \left \{ \ln \left ( x+\sqrt {{x}^{2}-1} \right ) -\ln \left ( y \left ( x \right ) +\sqrt { \left ( y \left ( x \right ) \right ) ^{2}-1} \right ) +{\it \_C1}=0 \right \} \]
Sage: cpu = 1.22 (sec), leaf count = 0 \[ \left [\log \left (2 \, \sqrt {y\left (x\right )^{2} - 1} + 2 \, y\left (x\right )\right ) = c + \log \left (2 \, x + 2 \, \sqrt {x^{2} - 1}\right ), \text {\texttt {separable}}\right ] \]