2.1 problem Ex 1

Internal problem ID [11137]

Book: An elementary treatise on differential equations by Abraham Cohen. DC heath publishers. 1906
Section: Chapter 2, differential equations of the first order and the first degree. Article 9. Variables searated or separable. Page 13
Problem number: Ex 1.
ODE order: 1.
ODE degree: 1.

CAS Maple gives this as type [_separable]

\[ \boxed {\sec \left (x \right ) \cos \left (y\right )^{2}-\cos \left (x \right ) \sin \left (y\right ) y^{\prime }=0} \]

Solution by Maple

Time used: 0.0 (sec). Leaf size: 11

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

\[ y \left (x \right ) = \arccos \left (\frac {1}{\tan \left (x \right )+c_{1}}\right ) \]

Solution by Mathematica

Time used: 1.366 (sec). Leaf size: 45

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

\begin{align*} y(x)\to -\sec ^{-1}(\tan (x)+2 c_1) y(x)\to \sec ^{-1}(\tan (x)+2 c_1) y(x)\to -\frac {\pi }{2} y(x)\to \frac {\pi }{2} \end{align*}