2.7 problem 7

Internal problem ID [4185]

Book: A treatise on ordinary and partial differential equations by William Woolsey Johnson. 1913
Section: Chapter 2, Equations of the first order and degree. page 20
Problem number: 7.
ODE order: 1.
ODE degree: 1.

CAS Maple gives this as type [_separable]

Solve \begin {gather*} \boxed {y^{\prime }-\frac {1+y^{2}}{x^{2}+1}=0} \end {gather*}

Solution by Maple

Time used: 0.016 (sec). Leaf size: 9

dsolve(diff(y(x),x)=(y(x)^2+1)/(x^2+1),y(x), singsol=all)
 

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

Solution by Mathematica

Time used: 0.371 (sec). Leaf size: 25

DSolve[y'[x]==(y[x]^2+1)/(x^2+1),y[x],x,IncludeSingularSolutions -> True]
 

\begin{align*} y(x)\to \tan (\text {ArcTan}(x)+c_1) \\ y(x)\to -i \\ y(x)\to i \\ \end{align*}