61.10.2 problem 15

Internal problem ID [12189]
Book : Handbook of exact solutions for ordinary differential equations. By Polyanin and Zaitsev. Second edition
Section : Chapter 1, section 1.2. Riccati Equation. subsection 1.2.6-2. Equations with cosine.
Problem number : 15
Date solved : Tuesday, January 28, 2025 at 12:58:19 AM
CAS classification : [_Riccati]

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

Solution by Maple

Time used: 0.005 (sec). Leaf size: 272

dsolve(diff(y(x),x)=y(x)^2-a^2+a*lambda*cos(lambda*x)+a^2*cos(lambda*x)^2,y(x), singsol=all)
 
\[ y = \frac {\left (2 a c_{1} \sin \left (\lambda x \right ) \cos \left (\frac {\lambda x}{2}\right )+c_{1} \lambda \sin \left (\frac {\lambda x}{2}\right )\right ) \operatorname {HeunC}\left (\frac {4 a}{\lambda }, \frac {1}{2}, -\frac {1}{2}, -\frac {2 a}{\lambda }, \frac {8 a +3 \lambda }{8 \lambda }, \frac {\cos \left (\lambda x \right )}{2}+\frac {1}{2}\right )+2 \left (\operatorname {HeunC}\left (\frac {4 a}{\lambda }, -\frac {1}{2}, -\frac {1}{2}, -\frac {2 a}{\lambda }, \frac {8 a +3 \lambda }{8 \lambda }, \frac {\cos \left (\lambda x \right )}{2}+\frac {1}{2}\right ) a +\frac {\lambda \left (\operatorname {HeunCPrime}\left (\frac {4 a}{\lambda }, \frac {1}{2}, -\frac {1}{2}, -\frac {2 a}{\lambda }, \frac {8 a +3 \lambda }{8 \lambda }, \frac {\cos \left (\lambda x \right )}{2}+\frac {1}{2}\right ) c_{1} \cos \left (\frac {\lambda x}{2}\right )+\operatorname {HeunCPrime}\left (\frac {4 a}{\lambda }, -\frac {1}{2}, -\frac {1}{2}, -\frac {2 a}{\lambda }, \frac {8 a +3 \lambda }{8 \lambda }, \frac {\cos \left (\lambda x \right )}{2}+\frac {1}{2}\right )\right )}{2}\right ) \sin \left (\lambda x \right )}{2 \operatorname {HeunC}\left (\frac {4 a}{\lambda }, \frac {1}{2}, -\frac {1}{2}, -\frac {2 a}{\lambda }, \frac {8 a +3 \lambda }{8 \lambda }, \frac {\cos \left (\lambda x \right )}{2}+\frac {1}{2}\right ) \cos \left (\frac {\lambda x}{2}\right ) c_{1} +2 \operatorname {HeunC}\left (\frac {4 a}{\lambda }, -\frac {1}{2}, -\frac {1}{2}, -\frac {2 a}{\lambda }, \frac {8 a +3 \lambda }{8 \lambda }, \frac {\cos \left (\lambda x \right )}{2}+\frac {1}{2}\right )} \]

Solution by Mathematica

Time used: 1.618 (sec). Leaf size: 156

DSolve[D[y[x],x]==y[x]^2-a^2+a*\[Lambda]*Cos[\[Lambda]*x]+a^2*Cos[\[Lambda]*x]^2,y[x],x,IncludeSingularSolutions -> True]
 
\begin{align*} y(x)\to \frac {c_1 \left (-\exp \left (\int _1^x2 a \sin (\lambda K[1])dK[1]\right )\right )+a c_1 \sin (\lambda x) \int _1^x\exp \left (\int _1^{K[2]}2 a \sin (\lambda K[1])dK[1]\right )dK[2]+a \sin (\lambda x)}{1+c_1 \int _1^x\exp \left (\int _1^{K[2]}2 a \sin (\lambda K[1])dK[1]\right )dK[2]} \\ y(x)\to a \sin (\lambda x)-\frac {\exp \left (\int _1^x2 a \sin (\lambda K[1])dK[1]\right )}{\int _1^x\exp \left (\int _1^{K[2]}2 a \sin (\lambda K[1])dK[1]\right )dK[2]} \\ \end{align*}