1.21 problem 24

1.21.1 Solving as quadrature ode
1.21.2 Maple step by step solution

Internal problem ID [12884]
Internal file name [OUTPUT/11537_Monday_November_06_2023_01_33_07_PM_3482729/index.tex]

Book: DIFFERENTIAL EQUATIONS by Paul Blanchard, Robert L. Devaney, Glen R. Hall. 4th edition. Brooks/Cole. Boston, USA. 2012
Section: Chapter 1. First-Order Differential Equations. Exercises section 1.2. page 33
Problem number: 24.
ODE order: 1.
ODE degree: 1.

The type(s) of ODE detected by this program : "quadrature"

Maple gives the following as the ode type

[_quadrature]

\[ \boxed {y^{\prime }-\sec \left (y\right )=0} \]

1.21.1 Solving as quadrature ode

Integrating both sides gives \begin {align*} \int \frac {1}{\sec \left (y \right )}d y &= x +c_{1}\\ \sin \left (y \right )&=x +c_{1} \end {align*}

Solving for \(y\) gives these solutions \begin {align*} y_1&=\arcsin \left (x +c_{1} \right ) \end {align*}

Summary

The solution(s) found are the following \begin{align*} \tag{1} y &= \arcsin \left (x +c_{1} \right ) \\ \end{align*}

Figure 62: Slope field plot

Verification of solutions

\[ y = \arcsin \left (x +c_{1} \right ) \] Verified OK.

1.21.2 Maple step by step solution

\[ \begin {array}{lll} & {} & \textrm {Let's solve}\hspace {3pt} \\ {} & {} & y^{\prime }-\sec \left (y\right )=0 \\ \bullet & {} & \textrm {Highest derivative means the order of the ODE is}\hspace {3pt} 1 \\ {} & {} & y^{\prime } \\ \bullet & {} & \textrm {Solve for the highest derivative}\hspace {3pt} \\ {} & {} & y^{\prime }=\sec \left (y\right ) \\ \bullet & {} & \textrm {Separate variables}\hspace {3pt} \\ {} & {} & \frac {y^{\prime }}{\sec \left (y\right )}=1 \\ \bullet & {} & \textrm {Integrate both sides with respect to}\hspace {3pt} x \\ {} & {} & \int \frac {y^{\prime }}{\sec \left (y\right )}d x =\int 1d x +c_{1} \\ \bullet & {} & \textrm {Evaluate integral}\hspace {3pt} \\ {} & {} & \sin \left (y\right )=x +c_{1} \\ \bullet & {} & \textrm {Solve for}\hspace {3pt} y \\ {} & {} & y=\arcsin \left (x +c_{1} \right ) \end {array} \]

Maple trace

`Methods for first order ODEs: 
--- Trying classification methods --- 
trying a quadrature 
trying 1st order linear 
trying Bernoulli 
trying separable 
<- separable successful`
 

Solution by Maple

Time used: 0.0 (sec). Leaf size: 8

dsolve(diff(y(x),x)=sec(y(x)),y(x), singsol=all)
 

\[ y \left (x \right ) = \arcsin \left (c_{1} +x \right ) \]

Solution by Mathematica

Time used: 0.35 (sec). Leaf size: 10

DSolve[y'[x]==Sec[y[x]],y[x],x,IncludeSingularSolutions -> True]
 

\[ y(x)\to \arcsin (x+c_1) \]