1.17 problem 17

Internal problem ID [4419]

Book: Fundamentals of Differential Equations. By Nagle, Saff and Snider. 9th edition. Boston. Pearson 2018.
Section: Chapter 2, First order differential equations. Section 2.2, Separable Equations. Exercises. page 46
Problem number: 17.
ODE order: 1.
ODE degree: 1.

CAS Maple gives this as type [_separable]

\[ \boxed {y^{\prime }-\left (1+y^{2}\right ) \tan \left (x \right )=0} \] With initial conditions \begin {align*} \left [y \left (0\right ) = \sqrt {3}\right ] \end {align*}

Solution by Maple

Time used: 0.062 (sec). Leaf size: 12

dsolve([diff(y(x),x)=(1+y(x)^2)*tan(x),y(0) = 3^(1/2)],y(x), singsol=all)
 

\[ y \left (x \right ) = \cot \left (\frac {\pi }{6}+\ln \left (\cos \left (x \right )\right )\right ) \]

Solution by Mathematica

Time used: 0.264 (sec). Leaf size: 15

DSolve[{y'[x]==(1+y[x]^2)*Tan[x],{y[0]==Sqrt[3]}},y[x],x,IncludeSingularSolutions -> True]
 

\begin{align*} y(x)\to \cot \left (\log (\cos (x))+\frac {\pi }{6}\right ) \\ \end{align*}