7.1.6 problem 6

Internal problem ID [6]
Book : Elementary Differential Equations. By C. Henry Edwards, David E. Penney and David Calvis. 6th edition. 2008
Section : Chapter 1. First order differential equations. Section 1.2. Problems at page 17
Problem number : 6
Date solved : Saturday, March 29, 2025 at 04:25:29 PM
CAS classification : [_quadrature]

\begin{align*} y^{\prime }&=x \sqrt {x^{2}+9} \end{align*}

With initial conditions

\begin{align*} y \left (-4\right )&=0 \end{align*}

✓ Maple. Time used: 0.036 (sec). Leaf size: 27

ode:=diff(y(x),x) = x*(x^2+9)^(1/2); 
ic:=y(-4) = 0; 
dsolve([ode,ic],y(x), singsol=all);
 

\[ y = \frac {\sqrt {x^{2}+9}\, x^{2}}{3}+3 \sqrt {x^{2}+9}-\frac {125}{3} \]

✓ Mathematica. Time used: 0.005 (sec). Leaf size: 20

ode=D[y[x],x]==x*Sqrt[x^2+9]; 
ic={y[-4]==0}; 
DSolve[{ode,ic},y[x],x,IncludeSingularSolutions->True]
 

\[ y(x)\to \frac {1}{3} \left (\left (x^2+9\right )^{3/2}-125\right ) \]

✓ Sympy. Time used: 0.232 (sec). Leaf size: 29

from sympy import * 
x = symbols("x") 
y = Function("y") 
ode = Eq(-x*sqrt(x**2 + 9) + Derivative(y(x), x),0) 
ics = {y(-4): 0} 
dsolve(ode,func=y(x),ics=ics)
 

\[ y{\left (x \right )} = \frac {x^{2} \sqrt {x^{2} + 9}}{3} + 3 \sqrt {x^{2} + 9} - \frac {125}{3} \]