1.6 problem 7

1.6.1 Solving as quadrature ode
1.6.2 Maple step by step solution

Internal problem ID [14938]
Internal file name [OUTPUT/14948_Monday_April_15_2024_12_04_12_AM_48849731/index.tex]

Book: A book of problems in ordinary differential equations. M.L. KRASNOV, A.L. KISELYOV, G.I. MARKARENKO. MIR, MOSCOW. 1983
Section: Section 1. Basic concepts and definitions. Exercises page 18
Problem number: 7.
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]

\[ \boxed {y^{\prime }-\sqrt {1-y^{2}}=0} \]

1.6.1 Solving as quadrature ode

Integrating both sides gives \begin {align*} \int \frac {1}{\sqrt {-y^{2}+1}}d y &= x +c_{1}\\ \arcsin \left (y \right )&=x +c_{1} \end {align*}

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

Summary

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

Figure 10: Slope field plot

Verification of solutions

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

1.6.2 Maple step by step solution

\[ \begin {array}{lll} & {} & \textrm {Let's solve}\hspace {3pt} \\ {} & {} & y^{\prime }-\sqrt {1-y^{2}}=0 \\ \bullet & {} & \textrm {Highest derivative means the order of the ODE is}\hspace {3pt} 1 \\ {} & {} & y^{\prime } \\ \bullet & {} & \textrm {Solve for the highest derivative}\hspace {3pt} \\ {} & {} & y^{\prime }=\sqrt {1-y^{2}} \\ \bullet & {} & \textrm {Separate variables}\hspace {3pt} \\ {} & {} & \frac {y^{\prime }}{\sqrt {1-y^{2}}}=1 \\ \bullet & {} & \textrm {Integrate both sides with respect to}\hspace {3pt} x \\ {} & {} & \int \frac {y^{\prime }}{\sqrt {1-y^{2}}}d x =\int 1d x +c_{1} \\ \bullet & {} & \textrm {Evaluate integral}\hspace {3pt} \\ {} & {} & \arcsin \left (y\right )=x +c_{1} \\ \bullet & {} & \textrm {Solve for}\hspace {3pt} y \\ {} & {} & y=\sin \left (x +c_{1} \right ) \end {array} \]

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)=sqrt(1-y(x)^2),y(x), singsol=all)
 

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

Solution by Mathematica

Time used: 0.216 (sec). Leaf size: 28

DSolve[y'[x]==Sqrt[1-y[x]^2],y[x],x,IncludeSingularSolutions -> True]
 

\begin{align*} y(x)\to \cos (x+c_1) \\ y(x)\to -1 \\ y(x)\to 1 \\ y(x)\to \text {Interval}[\{-1,1\}] \\ \end{align*}