1.17 problem 2.3 (g)

1.17.1 Solving as quadrature ode
1.17.2 Maple step by step solution

Internal problem ID [13258]
Internal file name [OUTPUT/12430_Wednesday_February_14_2024_02_06_12_AM_1420928/index.tex]

Book: Ordinary Differential Equations. An introduction to the fundamentals. Kenneth B. Howell. second edition. CRC Press. FL, USA. 2020
Section: Chapter 2. Integration and differential equations. Additional exercises. page 32
Problem number: 2.3 (g).
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]

\[ \boxed {-\left (x^{2}-9\right ) y^{\prime }=-x} \]

1.17.1 Solving as quadrature ode

Integrating both sides gives \begin {align*} y &= \int { \frac {x}{x^{2}-9}\,\mathop {\mathrm {d}x}}\\ &= \frac {\ln \left (x^{2}-9\right )}{2}+c_{1} \end {align*}

Summary

The solution(s) found are the following \begin{align*} \tag{1} y &= \frac {\ln \left (x^{2}-9\right )}{2}+c_{1} \\ \end{align*}

Figure 32: Slope field plot

Verification of solutions

\[ y = \frac {\ln \left (x^{2}-9\right )}{2}+c_{1} \] Verified OK.

1.17.2 Maple step by step solution

\[ \begin {array}{lll} & {} & \textrm {Let's solve}\hspace {3pt} \\ {} & {} & -\left (x^{2}-9\right ) y^{\prime }=-x \\ \bullet & {} & \textrm {Highest derivative means the order of the ODE is}\hspace {3pt} 1 \\ {} & {} & y^{\prime } \\ \bullet & {} & \textrm {Solve for the highest derivative}\hspace {3pt} \\ {} & {} & y^{\prime }=\frac {x}{x^{2}-9} \\ \bullet & {} & \textrm {Integrate both sides with respect to}\hspace {3pt} x \\ {} & {} & \int y^{\prime }d x =\int \frac {x}{x^{2}-9}d x +c_{1} \\ \bullet & {} & \textrm {Evaluate integral}\hspace {3pt} \\ {} & {} & y=\frac {\ln \left (x^{2}-9\right )}{2}+c_{1} \\ \bullet & {} & \textrm {Solve for}\hspace {3pt} y \\ {} & {} & y=\frac {\ln \left (x^{2}-9\right )}{2}+c_{1} \end {array} \]

Maple trace

`Methods for first order ODEs: 
--- Trying classification methods --- 
trying a quadrature 
<- quadrature successful`
 

Solution by Maple

Time used: 0.0 (sec). Leaf size: 14

dsolve(x=(x^2-9)*diff(y(x),x),y(x), singsol=all)
 

\[ y \left (x \right ) = \frac {\ln \left (x^{2}-9\right )}{2}+c_{1} \]

Solution by Mathematica

Time used: 0.004 (sec). Leaf size: 18

DSolve[x==(x^2-9)*y'[x],y[x],x,IncludeSingularSolutions -> True]
 

\[ y(x)\to \frac {1}{2} \log \left (x^2-9\right )+c_1 \]