7.24 problem 199

Internal problem ID [2947]

Book: Ordinary differential equations and their solutions. By George Moseley Murphy. 1960
Section: Various 7
Problem number: 199.
ODE order: 1.
ODE degree: 1.

CAS Maple gives this as type [y=_G(x,y')]

Solve \begin {gather*} \boxed {y^{\prime } x +\left (\sin \relax (y)-3 x^{2} \cos \relax (y)\right ) \cos \relax (y)=0} \end {gather*}

Solution by Maple

Time used: 0.009 (sec). Leaf size: 16

dsolve(x*diff(y(x),x)+(sin(y(x))-3*x^2*cos(y(x)))*cos(y(x)) = 0,y(x), singsol=all)
 

\[ y \relax (x ) = \arctan \left (\frac {x^{3}+2 c_{1}}{x}\right ) \]

Solution by Mathematica

Time used: 3.68 (sec). Leaf size: 85

DSolve[x y'[x]+(Sin[y[x]]-3 x^2 Cos[y[x]]) Cos[y[x]]==0,y[x],x,IncludeSingularSolutions -> True]
 

\begin{align*} y(x)\to \text {ArcTan}\left (x^2+\frac {c_1}{2 x}\right ) \\ y(x)\to -\frac {1}{2} i \left (\log \left (-\frac {i}{2 x}\right )-\log \left (\frac {i}{2 x}\right )\right ) \\ y(x)\to \frac {1}{2} i \left (\log \left (-\frac {i}{2 x}\right )-\log \left (\frac {i}{2 x}\right )\right ) \\ \end{align*}