26.21 problem 757

Internal problem ID [3998]

Book: Ordinary differential equations and their solutions. By George Moseley Murphy. 1960
Section: Various 26
Problem number: 757.
ODE order: 1.
ODE degree: 2.

CAS Maple gives this as type [_quadrature]

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

Solution by Maple

Time used: 0.031 (sec). Leaf size: 68

dsolve(diff(y(x),x)^2 = a^2-y(x)^2,y(x), singsol=all)
 

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

Solution by Mathematica

Time used: 5.305 (sec). Leaf size: 111

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

\begin{align*} y(x)\to -\frac {a \tan (x-c_1)}{\sqrt {\sec ^2(x-c_1)}} y(x)\to \frac {a \tan (x-c_1)}{\sqrt {\sec ^2(x-c_1)}} y(x)\to -\frac {a \tan (x+c_1)}{\sqrt {\sec ^2(x+c_1)}} y(x)\to \frac {a \tan (x+c_1)}{\sqrt {\sec ^2(x+c_1)}} y(x)\to -a y(x)\to a \end{align*}