60.1.546 problem 549

Internal problem ID [10560]
Book : Differential Gleichungen, E. Kamke, 3rd ed. Chelsea Pub. NY, 1948
Section : Chapter 1, linear first order
Problem number : 549
Date solved : Monday, January 27, 2025 at 09:05:14 PM
CAS classification : [_quadrature]

\begin{align*} x^{2} \left (1+{y^{\prime }}^{2}\right )^{3}-a^{2}&=0 \end{align*}

Solution by Maple

Time used: 0.043 (sec). Leaf size: 585

dsolve(x^2*(diff(y(x),x)^2+1)^3-a^2=0,y(x), singsol=all)
 
\begin{align*} y &= \frac {-\sqrt {\frac {x \left (a^{2} x \right )^{{1}/{3}} \left (a^{2}-\left (a^{2} x \right )^{{2}/{3}}\right )}{a^{2}}}\, a^{2}+c_{1} \left (a^{2} x \right )^{{2}/{3}}+\left (a^{2} x \right )^{{2}/{3}} \sqrt {\frac {x \left (a^{2} x \right )^{{1}/{3}} \left (a^{2}-\left (a^{2} x \right )^{{2}/{3}}\right )}{a^{2}}}}{\left (a^{2} x \right )^{{2}/{3}}} \\ y &= \frac {\left (a^{2}-\left (a^{2} x \right )^{{2}/{3}}\right ) \sqrt {\frac {x \left (a^{2} x \right )^{{1}/{3}} \left (a^{2}-\left (a^{2} x \right )^{{2}/{3}}\right )}{a^{2}}}+c_{1} \left (a^{2} x \right )^{{2}/{3}}}{\left (a^{2} x \right )^{{2}/{3}}} \\ y &= -\frac {\sqrt {2}\, \sqrt {-x \left (i \sqrt {3}\, \left (a^{2} x \right )^{{1}/{3}}+\left (a^{2} x \right )^{{1}/{3}}+2 x \right )}\, \sqrt {\frac {x \left (a^{2} x \right )^{{1}/{3}} \left (2 i \left (a^{2} x \right )^{{2}/{3}}+i a^{2}-\sqrt {3}\, a^{2}\right )}{a^{2}}}\, \left (2 \left (a^{2} x \right )^{{2}/{3}}+a^{2}+i \sqrt {3}\, a^{2}\right )}{4 \sqrt {\left (i \left (a^{2} x \right )^{{1}/{3}}+2 i x -\sqrt {3}\, \left (a^{2} x \right )^{{1}/{3}}\right ) x}\, \left (a^{2} x \right )^{{2}/{3}}}+c_{1} \\ y &= \frac {\sqrt {2}\, \sqrt {-x \left (i \sqrt {3}\, \left (a^{2} x \right )^{{1}/{3}}+\left (a^{2} x \right )^{{1}/{3}}+2 x \right )}\, \sqrt {\frac {x \left (a^{2} x \right )^{{1}/{3}} \left (2 i \left (a^{2} x \right )^{{2}/{3}}+i a^{2}-\sqrt {3}\, a^{2}\right )}{a^{2}}}\, \left (2 \left (a^{2} x \right )^{{2}/{3}}+a^{2}+i \sqrt {3}\, a^{2}\right )}{4 \sqrt {\left (i \left (a^{2} x \right )^{{1}/{3}}+2 i x -\sqrt {3}\, \left (a^{2} x \right )^{{1}/{3}}\right ) x}\, \left (a^{2} x \right )^{{2}/{3}}}+c_{1} \\ y &= \frac {\sqrt {2}\, \left (\left (i \sqrt {3}-1\right ) a^{2}-2 \left (a^{2} x \right )^{{2}/{3}}\right ) \sqrt {\frac {\left (\left (i \sqrt {3}-1\right ) a^{2}-2 \left (a^{2} x \right )^{{2}/{3}}\right ) x \left (a^{2} x \right )^{{1}/{3}}}{a^{2}}}+4 c_{1} \left (a^{2} x \right )^{{2}/{3}}}{4 \left (a^{2} x \right )^{{2}/{3}}} \\ y &= -\frac {\left (-2 \left (a^{2} x \right )^{{2}/{3}} \sqrt {2}+a^{2} \left (i \sqrt {6}-\sqrt {2}\right )\right ) \sqrt {\frac {\left (\left (i \sqrt {3}-1\right ) a^{2}-2 \left (a^{2} x \right )^{{2}/{3}}\right ) x \left (a^{2} x \right )^{{1}/{3}}}{a^{2}}}-4 c_{1} \left (a^{2} x \right )^{{2}/{3}}}{4 \left (a^{2} x \right )^{{2}/{3}}} \\ \end{align*}

Solution by Mathematica

Time used: 0.116 (sec). Leaf size: 216

DSolve[-a^2 + x^2*(1 + D[y[x],x]^2)^3==0,y[x],x,IncludeSingularSolutions -> True]
 
\begin{align*} y(x)\to -x \left (\frac {a^{2/3}}{x^{2/3}}-1\right )^{3/2}+c_1 \\ y(x)\to x \left (\frac {a^{2/3}}{x^{2/3}}-1\right )^{3/2}+c_1 \\ y(x)\to c_1-x \left (-1-\frac {i \left (\sqrt {3}-i\right ) a^{2/3}}{2 x^{2/3}}\right )^{3/2} \\ y(x)\to x \left (-1-\frac {i \left (\sqrt {3}-i\right ) a^{2/3}}{2 x^{2/3}}\right )^{3/2}+c_1 \\ y(x)\to c_1-x \left (-1+\frac {i \left (\sqrt {3}+i\right ) a^{2/3}}{2 x^{2/3}}\right )^{3/2} \\ y(x)\to x \left (-1+\frac {i \left (\sqrt {3}+i\right ) a^{2/3}}{2 x^{2/3}}\right )^{3/2}+c_1 \\ \end{align*}