1.32 problem 32

Internal problem ID [4991]

Book: Ordinary differential equations and calculus of variations. Makarets and Reshetnyak. Wold Scientific. Singapore. 1995
Section: Chapter 1. First order differential equations. Section 1.1 Separable equations problems. page 7
Problem number: 32.
ODE order: 1.
ODE degree: 1.

CAS Maple gives this as type [[_homogeneous, `class C`], _dAlembert]

\[ \boxed {y^{\prime }-2 \sqrt {2 x +y+1}=0} \]

Solution by Maple

Time used: 0.031 (sec). Leaf size: 56

dsolve(diff(y(x),x)=2*sqrt(2*x+y(x)+1),y(x), singsol=all)
 

\[ x -\sqrt {2 x +y \left (x \right )+1}-\frac {\ln \left (-1+\sqrt {2 x +y \left (x \right )+1}\right )}{2}+\frac {\ln \left (\sqrt {2 x +y \left (x \right )+1}+1\right )}{2}+\frac {\ln \left (y \left (x \right )+2 x \right )}{2}-c_{1} = 0 \]

Solution by Mathematica

Time used: 8.962 (sec). Leaf size: 47

DSolve[y'[x]==2*Sqrt[2*x+y[x]+1],y[x],x,IncludeSingularSolutions -> True]
 

\begin{align*} y(x)\to -2 x+W\left (-e^{-x-\frac {3}{2}+c_1}\right ) \left (2+W\left (-e^{-x-\frac {3}{2}+c_1}\right )\right ) \\ y(x)\to -2 x \\ \end{align*}