\[ \sqrt {x^2-1} y'(x)-\sqrt {y(x)^2-1}=0 \] ✓ Mathematica : cpu = 0.0468695 (sec), leaf count = 44
\[\left \{\left \{y(x)\to \frac {1}{2} e^{-c_1} \left (\left (e^{2 c_1}-1\right ) \sqrt {x^2-1}+\left (e^{2 c_1}+1\right ) x\right )\right \}\right \}\]
✓ Maple : cpu = 0.01 (sec), leaf count = 29
\[ \left \{ \ln \left ( x+\sqrt {{x}^{2}-1} \right ) -\ln \left ( y \left ( x \right ) +\sqrt { \left ( y \left ( x \right ) \right ) ^{2}-1} \right ) +{\it \_C1}=0 \right \} \]