1.64 problem 64

Internal problem ID [8401]

Book: Differential Gleichungen, E. Kamke, 3rd ed. Chelsea Pub. NY, 1948
Section: Chapter 1, linear first order
Problem number: 64.
ODE order: 1.
ODE degree: 1.

CAS Maple gives this as type [[_1st_order, `_with_symmetry_[F(x),G(x)*y+H(x)]`]]

\[ \boxed {y^{\prime }-\sqrt {\frac {a y^{2}+b y+c}{a \,x^{2}+b x +c}}=0} \]

Solution by Maple

Time used: 0.016 (sec). Leaf size: 153

dsolve(diff(y(x),x) - sqrt((a*y(x)^2+b*y(x)+c)/(a*x^2+b*x+c))=0,y(x), singsol=all)
 

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

Solution by Mathematica

Time used: 5.542 (sec). Leaf size: 142

DSolve[y'[x]- Sqrt[(a*y[x]^2+b*y[x]+c)/(a*x^2+b*x+c)]==0,y[x],x,IncludeSingularSolutions -> True]
                                                                                    
                                                                                    
 

\begin{align*} y(x)\to \frac {e^{-\sqrt {a} c_1} \left (2 \sqrt {a} \left (-1+e^{2 \sqrt {a} c_1}\right ) \sqrt {x (a x+b)+c}+b \left (-1+e^{\sqrt {a} c_1}\right ){}^2+2 a x \left (1+e^{2 \sqrt {a} c_1}\right )\right )}{4 a} \\ y(x)\to -\frac {\sqrt {b^2-4 a c}+b}{2 a} \\ y(x)\to \frac {\sqrt {b^2-4 a c}-b}{2 a} \\ \end{align*}