4.69 problem 66

4.69.1 Solving as quadrature ode
4.69.2 Maple step by step solution

Internal problem ID [14226]
Internal file name [OUTPUT/13907_Saturday_March_09_2024_03_57_52_PM_44719709/index.tex]

Book: INTRODUCTORY DIFFERENTIAL EQUATIONS. Martha L. Abell, James P. Braselton. Fourth edition 2014. ElScAe. 2014
Section: Chapter 2. First Order Equations. Exercises 2.2, page 39
Problem number: 66.
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]

\[ \boxed {y^{\prime }-16 y+8 y^{2}=0} \]

4.69.1 Solving as quadrature ode

Integrating both sides gives \begin {align*} \int \frac {1}{-8 y^{2}+16 y}d y &= t +c_{1}\\ -\frac {\ln \left (y -2\right )}{16}+\frac {\ln \left (y \right )}{16}&=t +c_{1} \end {align*}

Solving for \(y\) gives these solutions \begin {align*} y_1&=\frac {2 \,{\mathrm e}^{16 t +16 c_{1}}}{-1+{\mathrm e}^{16 t +16 c_{1}}}\\ &=\frac {2 \,{\mathrm e}^{16 t} c_{1}^{16}}{-1+{\mathrm e}^{16 t} c_{1}^{16}} \end {align*}

Summary

The solution(s) found are the following \begin{align*} \tag{1} y &= \frac {2 \,{\mathrm e}^{16 t} c_{1}^{16}}{-1+{\mathrm e}^{16 t} c_{1}^{16}} \\ \end{align*}

Figure 241: Slope field plot

Verification of solutions

\[ y = \frac {2 \,{\mathrm e}^{16 t} c_{1}^{16}}{-1+{\mathrm e}^{16 t} c_{1}^{16}} \] Verified OK.

4.69.2 Maple step by step solution

\[ \begin {array}{lll} & {} & \textrm {Let's solve}\hspace {3pt} \\ {} & {} & y^{\prime }-16 y+8 y^{2}=0 \\ \bullet & {} & \textrm {Highest derivative means the order of the ODE is}\hspace {3pt} 1 \\ {} & {} & y^{\prime } \\ \bullet & {} & \textrm {Solve for the highest derivative}\hspace {3pt} \\ {} & {} & y^{\prime }=16 y-8 y^{2} \\ \bullet & {} & \textrm {Separate variables}\hspace {3pt} \\ {} & {} & \frac {y^{\prime }}{16 y-8 y^{2}}=1 \\ \bullet & {} & \textrm {Integrate both sides with respect to}\hspace {3pt} t \\ {} & {} & \int \frac {y^{\prime }}{16 y-8 y^{2}}d t =\int 1d t +c_{1} \\ \bullet & {} & \textrm {Evaluate integral}\hspace {3pt} \\ {} & {} & -\frac {\ln \left (y-2\right )}{16}+\frac {\ln \left (y\right )}{16}=t +c_{1} \\ \bullet & {} & \textrm {Solve for}\hspace {3pt} y \\ {} & {} & y=\frac {2 \,{\mathrm e}^{16 t +16 c_{1}}}{-1+{\mathrm e}^{16 t +16 c_{1}}} \end {array} \]

Maple trace

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

Solution by Maple

Time used: 0.016 (sec). Leaf size: 17

dsolve(diff(y(t),t)=16*y(t)-8*y(t)^2,y(t), singsol=all)
 

\[ y \left (t \right ) = \frac {2}{1+2 \,{\mathrm e}^{-16 t} c_{1}} \]

Solution by Mathematica

Time used: 0.278 (sec). Leaf size: 36

DSolve[y'[t]==16*y[t]-8*y[t]^2,y[t],t,IncludeSingularSolutions -> True]
 

\begin{align*} y(t)\to \frac {2 e^{16 t}}{e^{16 t}+e^{2 c_1}} \\ y(t)\to 0 \\ y(t)\to 2 \\ \end{align*}