2.1604   ODE No. 1604

\[ y''(x)-e^{y(x)}=0 \] Mathematica : cpu = 0.0404187 (sec), leaf count = 34


\[\left \{\left \{y(x)\to \log \left (\frac {1}{2} c_1 \left (-1+\tanh ^2\left (\frac {1}{2} \sqrt {c_1 (x+c_2){}^2}\right )\right )\right )\right \}\right \}\] Maple : cpu = 0.231 (sec), leaf count = 23


\[y \relax (x ) = \ln \left (\frac {\tan ^{2}\left (\frac {x +c_{2}}{2 c_{1}}\right )+1}{2 c_{1}^{2}}\right )\]