\[ x y'(x)+\sqrt {y'(x)^2+1}-y(x)=0 \] ✓ Mathematica : cpu = 0.006146 (sec), leaf count = 20
\[\left \{\left \{y(x)\to c_1 x+\sqrt {1+c_1{}^2}\right \}\right \}\] ✓ Maple : cpu = 0.033 (sec), leaf count = 15
\[y \relax (x ) = \sqrt {c_{1}^{2}+1}+x c_{1}\]