#### 2.556   ODE No. 556

$x y'(x)^2+\sqrt {y'(x)^2+1}+y(x)=0$ Mathematica : cpu = 4.46358 (sec), leaf count = 60

$\text {Solve}\left [\left \{x=\frac {c_1}{(\text {K\537938}+1)^2}+\frac {-\sqrt {\text {K\537938}^2+1}-\sinh ^{-1}(\text {K\537938})}{(\text {K\537938}+1)^2},y(x)=\text {K\537938}^2 (-x)-\sqrt {\text {K\537938}^2+1}\right \},\{y(x),\text {K\537938}\}\right ]$ Maple : cpu = 0.141 (sec), leaf count = 581

$\left \{ {{\it \_C1}\,{x}^{2} \left ( \sqrt {-4\,xy \left ( x \right ) +2+2\,\sqrt {4\,{x}^{2}-4\,xy \left ( x \right ) +1}}-2\,x \right ) ^{-2}}+x+2\,{\frac {{x}^{2}}{ \left ( \sqrt {-4\,xy \left ( x \right ) +2+2\,\sqrt {4\,{x}^{2}-4\,xy \left ( x \right ) +1}}-2\,x \right ) ^{2}} \left ( \sqrt {2}\sqrt {{\frac {2\,{x}^{2}-2\,xy \left ( x \right ) +\sqrt {4\,{x}^{2}-4\,xy \left ( x \right ) +1}+1}{{x}^{2}}}}-2\,{\it Arcsinh} \left ( 1/2\,{\frac {\sqrt {-4\,xy \left ( x \right ) +2+2\,\sqrt {4\,{x}^{2}-4\,xy \left ( x \right ) +1}}}{x}} \right ) \right ) }=0,{{\it \_C1}\,{x}^{2} \left ( \sqrt {-4\,xy \left ( x \right ) +2+2\,\sqrt {4\,{x}^{2}-4\,xy \left ( x \right ) +1}}+2\,x \right ) ^{-2}}+x+2\,{\frac {{x}^{2}}{ \left ( \sqrt {-4\,xy \left ( x \right ) +2+2\,\sqrt {4\,{x}^{2}-4\,xy \left ( x \right ) +1}}+2\,x \right ) ^{2}} \left ( \sqrt {2}\sqrt {{\frac {2\,{x}^{2}-2\,xy \left ( x \right ) +\sqrt {4\,{x}^{2}-4\,xy \left ( x \right ) +1}+1}{{x}^{2}}}}+2\,{\it Arcsinh} \left ( 1/2\,{\frac {\sqrt {-4\,xy \left ( x \right ) +2+2\,\sqrt {4\,{x}^{2}-4\,xy \left ( x \right ) +1}}}{x}} \right ) \right ) }=0,{{\it \_C1}\,{x}^{2} \left ( \sqrt {-4\,xy \left ( x \right ) -2\,\sqrt {4\,{x}^{2}-4\,xy \left ( x \right ) +1}+2}-2\,x \right ) ^{-2}}+x+2\,{\frac {{x}^{2}}{ \left ( \sqrt {-4\,xy \left ( x \right ) -2\,\sqrt {4\,{x}^{2}-4\,xy \left ( x \right ) +1}+2}-2\,x \right ) ^{2}} \left ( -2\,{\it Arcsinh} \left ( 1/2\,{\frac {\sqrt {-4\,xy \left ( x \right ) -2\,\sqrt {4\,{x}^{2}-4\,xy \left ( x \right ) +1}+2}}{x}} \right ) +\sqrt {{\frac {4\,{x}^{2}-4\,xy \left ( x \right ) -2\,\sqrt {4\,{x}^{2}-4\,xy \left ( x \right ) +1}+2}{{x}^{2}}}} \right ) }=0,{{\it \_C1}\,{x}^{2} \left ( \sqrt {-4\,xy \left ( x \right ) -2\,\sqrt {4\,{x}^{2}-4\,xy \left ( x \right ) +1}+2}+2\,x \right ) ^{-2}}+x+2\,{\frac {{x}^{2}}{ \left ( \sqrt {-4\,xy \left ( x \right ) -2\,\sqrt {4\,{x}^{2}-4\,xy \left ( x \right ) +1}+2}+2\,x \right ) ^{2}} \left ( 2\,{\it Arcsinh} \left ( 1/2\,{\frac {\sqrt {-4\,xy \left ( x \right ) -2\,\sqrt {4\,{x}^{2}-4\,xy \left ( x \right ) +1}+2}}{x}} \right ) +\sqrt {{\frac {4\,{x}^{2}-4\,xy \left ( x \right ) -2\,\sqrt {4\,{x}^{2}-4\,xy \left ( x \right ) +1}+2}{{x}^{2}}}} \right ) }=0 \right \}$