56.38.9 problem Ex 9

Internal problem ID [14301]
Book : An elementary treatise on differential equations by Abraham Cohen. DC heath publishers. 1906
Section : Chapter IX, Miscellaneous methods for solving equations of higher order than first. Article 62. Summary. Page 144
Problem number : Ex 9
Date solved : Thursday, October 02, 2025 at 09:30:21 AM
CAS classification : [[_2nd_order, _missing_x], [_2nd_order, _reducible, _mu_xy]]

\begin{align*} y^{\prime \prime }+{y^{\prime }}^{2}+1&=0 \end{align*}

✓ Maple. Time used: 0.017 (sec). Leaf size: 15

ode:=diff(diff(y(x),x),x)+diff(y(x),x)^2+1 = 0; 
dsolve(ode,y(x), singsol=all);
 

\[ y = \ln \left (-c_1 \sin \left (x \right )+c_2 \cos \left (x \right )\right ) \]

✓ Mathematica. Time used: 1.052 (sec). Leaf size: 16

ode=D[y[x],{x,2}]+D[y[x],x]^2+1==0; 
ic={}; 
DSolve[{ode,ic},y[x],x,IncludeSingularSolutions->True]
 

\begin{align*} y(x)&\to \log (\cos (x-c_1))+c_2 \end{align*}

✓ Sympy. Time used: 0.715 (sec). Leaf size: 31

from sympy import * 
x = symbols("x") 
y = Function("y") 
ode = Eq(Derivative(y(x), x)**2 + Derivative(y(x), (x, 2)) + 1,0) 
ics = {} 
dsolve(ode,func=y(x),ics=ics)
 

\[ \left [ y{\left (x \right )} = C_{1} - \frac {\log {\left (\tan ^{2}{\left (C_{2} - x \right )} + 1 \right )}}{2}, \ y{\left (x \right )} = C_{1} - \frac {\log {\left (\tan ^{2}{\left (C_{2} - x \right )} + 1 \right )}}{2}\right ] \]