31.15 problem 914

Internal problem ID [3641]

Book: Ordinary differential equations and their solutions. By George Moseley Murphy. 1960
Section: Various 31
Problem number: 914.
ODE order: 1.
ODE degree: 2.

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

\[ \boxed {\left (1-x^{2}\right ) {y^{\prime }}^{2}-1+y^{2}=0} \]

Solution by Maple

Time used: 0.047 (sec). Leaf size: 166

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

\begin{align*} y \left (x \right ) = -1 \\ y \left (x \right ) = 1 \\ \frac {\sqrt {\left (y \left (x \right )-1\right ) \left (y \left (x \right )+1\right )}\, \ln \left (y \left (x \right )+\sqrt {y \left (x \right )^{2}-1}\right )}{\sqrt {y \left (x \right )-1}\, \sqrt {y \left (x \right )+1}}+\int _{}^{x}-\frac {\sqrt {\left (\textit {\_a}^{2}-1\right ) \left (y \left (x \right )^{2}-1\right )}}{\left (\textit {\_a}^{2}-1\right ) \sqrt {y \left (x \right )-1}\, \sqrt {y \left (x \right )+1}}d \textit {\_a} +c_{1} = 0 \\ \frac {\sqrt {\left (y \left (x \right )-1\right ) \left (y \left (x \right )+1\right )}\, \ln \left (y \left (x \right )+\sqrt {y \left (x \right )^{2}-1}\right )}{\sqrt {y \left (x \right )-1}\, \sqrt {y \left (x \right )+1}}+\int _{}^{x}\frac {\sqrt {\left (\textit {\_a}^{2}-1\right ) \left (y \left (x \right )^{2}-1\right )}}{\left (\textit {\_a}^{2}-1\right ) \sqrt {y \left (x \right )-1}\, \sqrt {y \left (x \right )+1}}d \textit {\_a} +c_{1} = 0 \\ \end{align*}

Solution by Mathematica

Time used: 5.147 (sec). Leaf size: 218

DSolve[(1-x^2) (y'[x])^2==1-y[x]^2,y[x],x,IncludeSingularSolutions -> True]
 

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