Internal problem ID [2626]
Internal file name [OUTPUT/2118_Sunday_June_05_2022_02_49_11_AM_50037576/index.tex]
Book: Differential equations and linear algebra, Stephen W. Goode and Scott A Annin. Fourth
edition, 2015
Section: Chapter 1, First-Order Differential Equations. Section 1.4, Separable Differential
Equations. page 43
Problem number: Problem 5.
ODE order: 1.
ODE degree: 1.
The type(s) of ODE detected by this program :
Maple gives the following as the ode type
[_separable]
\[ \boxed {y-\left (x -1\right ) y^{\prime }=0} \]
In canonical form the ODE is \begin {align*} y' &= F(x,y)\\ &= f( x) g(y)\\ &= \frac {y}{x -1} \end {align*}
Where \(f(x)=\frac {1}{x -1}\) and \(g(y)=y\). Integrating both sides gives \begin {align*} \frac {1}{y} \,dy &= \frac {1}{x -1} \,d x\\ \int { \frac {1}{y} \,dy} &= \int {\frac {1}{x -1} \,d x}\\ \ln \left (y \right )&=\ln \left (x -1\right )+c_{1}\\ y&={\mathrm e}^{\ln \left (x -1\right )+c_{1}}\\ &=c_{1} \left (x -1\right ) \end {align*}
Summary
The solution(s) found are the following \begin{align*} \tag{1} y &= c_{1} \left (x -1\right ) \\ \end{align*}
Verification of solutions
\[ y = c_{1} \left (x -1\right ) \] Verified OK.
\[ \begin {array}{lll} & {} & \textrm {Let's solve}\hspace {3pt} \\ {} & {} & y-\left (x -1\right ) y^{\prime }=0 \\ \bullet & {} & \textrm {Highest derivative means the order of the ODE is}\hspace {3pt} 1 \\ {} & {} & y^{\prime } \\ \bullet & {} & \textrm {Solve for the highest derivative}\hspace {3pt} \\ {} & {} & y^{\prime }=\frac {y}{x -1} \\ \bullet & {} & \textrm {Separate variables}\hspace {3pt} \\ {} & {} & \frac {y^{\prime }}{y}=\frac {1}{x -1} \\ \bullet & {} & \textrm {Integrate both sides with respect to}\hspace {3pt} x \\ {} & {} & \int \frac {y^{\prime }}{y}d x =\int \frac {1}{x -1}d x +c_{1} \\ \bullet & {} & \textrm {Evaluate integral}\hspace {3pt} \\ {} & {} & \ln \left (y\right )=\ln \left (x -1\right )+c_{1} \\ \bullet & {} & \textrm {Solve for}\hspace {3pt} y \\ {} & {} & y={\mathrm e}^{c_{1}} \left (x -1\right ) \end {array} \]
Maple trace
`Methods for first order ODEs: --- Trying classification methods --- trying a quadrature trying 1st order linear <- 1st order linear successful`
✓ Solution by Maple
Time used: 0.0 (sec). Leaf size: 9
dsolve(y(x)-(x-1)*diff(y(x),x)=0,y(x), singsol=all)
\[ y \left (x \right ) = c_{1} \left (x -1\right ) \]
✓ Solution by Mathematica
Time used: 0.023 (sec). Leaf size: 16
DSolve[y[x]-(x-1)*y'[x]==0,y[x],x,IncludeSingularSolutions -> True]
\begin{align*} y(x)\to c_1 (x-1) \\ y(x)\to 0 \\ \end{align*}