18.21 problem 21

Internal problem ID [2293]

Book: Differential Equations by Alfred L. Nelson, Karl W. Folley, Max Coral. 3rd ed. DC heath. Boston. 1964
Section: Exercise 35, page 157
Problem number: 21.
ODE order: 2.
ODE degree: 1.

CAS Maple gives this as type [[_2nd_order, _missing_x], [_2nd_order, _exact, _nonlinear], _Liouville, [_2nd_order, _reducible, _mu_x_y1], [_2nd_order, _reducible, _mu_xy]]

\[ \boxed {y y^{\prime \prime }+{y^{\prime }}^{2}=0} \]

Solution by Maple

Time used: 0.0 (sec). Leaf size: 33

dsolve(y(x)*diff(y(x),x$2)+diff(y(x),x)^2=0,y(x), singsol=all)
 

\begin{align*} y \left (x \right ) = 0 y \left (x \right ) = \sqrt {2 c_{1} x +2 c_{2}} y \left (x \right ) = -\sqrt {2 c_{1} x +2 c_{2}} \end{align*}

Solution by Mathematica

Time used: 0.161 (sec). Leaf size: 20

DSolve[y[x]*y''[x]+y'[x]^2==0,y[x],x,IncludeSingularSolutions -> True]
 

\[ y(x)\to c_2 \sqrt {2 x-c_1} \]