29.5.3 problem 118

Internal problem ID [4720]
Book : Ordinary differential equations and their solutions. By George Moseley Murphy. 1960
Section : Various 5
Problem number : 118
Date solved : Tuesday, March 04, 2025 at 07:10:29 PM
CAS classification : [_separable]

\begin{align*} y^{\prime }+\tan \left (x \right ) \cot \left (y\right )&=0 \end{align*}

✓ Maple. Time used: 0.246 (sec). Leaf size: 9

ode:=diff(y(x),x)+tan(x)*cot(y(x)) = 0; 
dsolve(ode,y(x), singsol=all);
 

\[ y \left (x \right ) = \arccos \left (\sec \left (x \right ) c_{1} \right ) \]

✓ Mathematica. Time used: 6.038 (sec). Leaf size: 47

ode=D[y[x],x]+Tan[x] Cot[y[x]]==0; 
ic={}; 
DSolve[{ode,ic},y[x],x,IncludeSingularSolutions->True]
 

\begin{align*} y(x)\to -\arccos \left (\frac {1}{2} c_1 \sec (x)\right ) \\ y(x)\to \arccos \left (\frac {1}{2} c_1 \sec (x)\right ) \\ y(x)\to -\frac {\pi }{2} \\ y(x)\to \frac {\pi }{2} \\ \end{align*}

✓ Sympy. Time used: 0.424 (sec). Leaf size: 20

from sympy import * 
x = symbols("x") 
y = Function("y") 
ode = Eq(tan(x)/tan(y(x)) + Derivative(y(x), x),0) 
ics = {} 
dsolve(ode,func=y(x),ics=ics)
 

\[ \left [ y{\left (x \right )} = - \operatorname {acos}{\left (\frac {C_{1}}{\cos {\left (x \right )}} \right )} + 2 \pi , \ y{\left (x \right )} = \operatorname {acos}{\left (\frac {C_{1}}{\cos {\left (x \right )}} \right )}\right ] \]