\[ -\frac {f'(x) y'(x)}{f(x)}+y(x) \left (-\frac {f''(x)}{2 f(x)}+\frac {3 f'(x)^2}{4 f(x)^2}+\frac {\left (\frac {1}{4}-v^2\right ) g'(x)^2}{g(x)^2}+g'(x)^2+\frac {g^3(x)}{2 g'(x)}-\frac {3 g''(x)^2}{4 g'(x)^2}\right )+y''(x)=0 \] ✗ Mathematica : cpu = 0.909063 (sec), leaf count = 0 , could not solve
DSolve[-((Derivative[1][f][x]*Derivative[1][y][x])/f[x]) + y[x]*((3*Derivative[1][f][x]^2)/(4*f[x]^2) + (g^3)[x]/(2*Derivative[1][g][x]) + Derivative[1][g][x]^2 + ((1/4 - v^2)*Derivative[1][g][x]^2)/g[x]^2 - Derivative[2][f][x]/(2*f[x]) - (3*Derivative[2][g][x]^2)/(4*Derivative[1][g][x]^2)) + Derivative[2][y][x] == 0, y[x], x]
✓ Maple : cpu = 0.144 (sec), leaf count = 31
\[ \left \{ y \left ( x \right ) =\sqrt {{\frac {f \left ( x \right ) g \left ( x \right ) }{{\frac {\rm d}{{\rm d}x}}g \left ( x \right ) }}} \left ( {{\sl Y}_{v}\left (g \left ( x \right ) \right )}{\it \_C2}+{{\sl J}_{v}\left (g \left ( x \right ) \right )}{\it \_C1} \right ) \right \} \]