1.14 problem 14

Internal problem ID [2557]

Book: Differential equations and linear algebra, Stephen W. Goode, second edition, 2000
Section: 1.4, page 36
Problem number: 14.
ODE order: 1.
ODE degree: 1.

CAS Maple gives this as type [_separable]

\[ \boxed {y^{\prime }+\frac {\sin \left (y+x \right )}{\sin \left (y\right ) \cos \left (x \right )}=1} \] With initial conditions \begin {align*} \left [y \left (\frac {\pi }{4}\right ) = \frac {\pi }{4}\right ] \end {align*}

Solution by Maple

Time used: 0.312 (sec). Leaf size: 9

dsolve([diff(y(x),x)=1- (sin(x+y(x)))/(sin(y(x))*cos(x)),y(1/4*Pi) = 1/4*Pi],y(x), singsol=all)
 

\[ y \left (x \right ) = \frac {\pi }{2}-\arcsin \left (\frac {\sec \left (x \right )}{2}\right ) \]

Solution by Mathematica

Time used: 6.234 (sec). Leaf size: 12

DSolve[{y'[x]==1- Sin[x+y[x]]/(Sin[y[x]]*Cos[x]),y[Pi/4]==Pi/4},y[x],x,IncludeSingularSolutions -> True]
 

\[ y(x)\to \arccos \left (\frac {\sec (x)}{2}\right ) \]