4.36 problem Problem 52

Internal problem ID [2191]

Book: Differential equations and linear algebra, Stephen W. Goode and Scott A Annin. Fourth edition, 2015
Section: Chapter 1, First-Order Differential Equations. Section 1.8, Change of Variables. page 79
Problem number: Problem 52.
ODE order: 1.
ODE degree: 1.

CAS Maple gives this as type [_Bernoulli]

\[ \boxed {y^{\prime }+\cot \left (x \right ) y-y^{3} \sin \left (x \right )^{3}=0} \] With initial conditions \begin {align*} \left [y \left (\frac {\pi }{2}\right ) = 1\right ] \end {align*}

Solution by Maple

Time used: 1.89 (sec). Leaf size: 34

dsolve([diff(y(x),x)+y(x)*cot(x)=y(x)^3*sin(x)^3,y(1/2*Pi) = 1],y(x), singsol=all)
 

\[ y \left (x \right ) = -\frac {\csc \left (x \right ) \sqrt {\left (2 \cos \left (x \right )-1\right )^{2} \left (1+2 \cos \left (x \right )\right )}}{4 \cos \left (x \right )^{2}-1} \]

Solution by Mathematica

Time used: 0.853 (sec). Leaf size: 20

DSolve[{y'[x]+y[x]*Cot[x]==y[x]^3*Sin[x]^3,{y[Pi/2]==1}},y[x],x,IncludeSingularSolutions -> True]
 

\begin{align*} y(x)\to \frac {1}{\sqrt {\sin ^2(x) (2 \cos (x)+1)}} \\ \end{align*}