3.12 problem 12

Internal problem ID [4989]

Book: Fundamentals of Differential Equations. By Nagle, Saff and Snider. 9th edition. Boston. Pearson 2018.
Section: Chapter 2, First order differential equations. Section 2.4, Exact equations. Exercises. page 64
Problem number: 12.
ODE order: 1.
ODE degree: 1.

CAS Maple gives this as type [_exact]

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

Solution by Maple

Time used: 0.016 (sec). Leaf size: 20

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

\[ \sin \left (x \right ) \cos \left (y \left (x \right )\right )+x^{2}-y \left (x \right )^{2}+c_{1} = 0 \]

Solution by Mathematica

Time used: 0.289 (sec). Leaf size: 25

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

\[ \text {Solve}\left [-2 x^2+2 y(x)^2-2 \sin (x) \cos (y(x))=c_1,y(x)\right ] \]