1.83 problem 83

Internal problem ID [7664]

Book: Differential Gleichungen, E. Kamke, 3rd ed. Chelsea Pub. NY, 1948
Section: Chapter 1, linear first order
Problem number: 83.
ODE order: 1.
ODE degree: 1.

CAS Maple gives this as type [y=_G(x,y')]

Solve \begin {gather*} \boxed {y^{\prime }-\tan \left (y x \right )=0} \end {gather*}

Solution by Maple

Time used: 0.125 (sec). Leaf size: 44

dsolve(diff(y(x),x) - tan(x*y(x))=0,y(x), singsol=all)
 

\[ y \relax (x ) = -i \RootOf \left (\sqrt {2}\, c_{1}-\erf \left (\frac {\left (x +\textit {\_Z} \right ) \sqrt {2}}{2}\right ) \sqrt {\pi }-\erf \left (\frac {\left (-x +\textit {\_Z} \right ) \sqrt {2}}{2}\right ) \sqrt {\pi }\right ) \]

Solution by Mathematica

Time used: 0.501 (sec). Leaf size: 69

DSolve[y'[x] - Tan[x*y[x]]==0,y[x],x,IncludeSingularSolutions -> True]
 

\[ \text {Solve}\left [\frac {1}{2} \sqrt {\frac {\pi }{2}} e^{\frac {x^2}{2}} \left (\text {Erfi}\left (\frac {y(x)-i x}{\sqrt {2}}\right )+\text {Erfi}\left (\frac {y(x)+i x}{\sqrt {2}}\right )\right )=c_1 e^{\frac {x^2}{2}},y(x)\right ] \]