3.7 problem 11

Internal problem ID [522]

Book: Elementary differential equations and boundary value problems, 10th ed., Boyce and DiPrima
Section: Section 2.4. Page 76
Problem number: 11.
ODE order: 1.
ODE degree: 1.

CAS Maple gives this as type [_separable]

\[ \boxed {y^{\prime }-\frac {t^{2}+1}{3 y-y^{2}}=0} \]

Solution by Maple

Time used: 0.0 (sec). Leaf size: 444

dsolve(diff(y(t),t) = (t^2+1)/(3*y(t)-y(t)^2),y(t), singsol=all)
 

\begin{align*} y \left (t \right ) &= \frac {\left (27-4 t^{3}-12 c_{1} -12 t +2 \sqrt {4 t^{6}+24 c_{1} t^{3}+24 t^{4}-54 t^{3}+36 c_{1}^{2}+72 c_{1} t +36 t^{2}-162 c_{1} -162 t}\right )^{\frac {1}{3}}}{2}+\frac {9}{2 \left (27-4 t^{3}-12 c_{1} -12 t +2 \sqrt {4 t^{6}+24 c_{1} t^{3}+24 t^{4}-54 t^{3}+36 c_{1}^{2}+72 c_{1} t +36 t^{2}-162 c_{1} -162 t}\right )^{\frac {1}{3}}}+\frac {3}{2} \\ y \left (t \right ) &= -\frac {\left (1+i \sqrt {3}\right ) \left (27-4 t^{3}-12 c_{1} -12 t +2 \sqrt {4}\, \sqrt {\left (t^{3}+3 t +3 c_{1} -\frac {27}{2}\right ) \left (t^{3}+3 c_{1} +3 t \right )}\right )^{\frac {2}{3}}-9 i \sqrt {3}-6 \left (27-4 t^{3}-12 c_{1} -12 t +2 \sqrt {4}\, \sqrt {\left (t^{3}+3 t +3 c_{1} -\frac {27}{2}\right ) \left (t^{3}+3 c_{1} +3 t \right )}\right )^{\frac {1}{3}}+9}{4 \left (27-4 t^{3}-12 c_{1} -12 t +2 \sqrt {4}\, \sqrt {\left (t^{3}+3 t +3 c_{1} -\frac {27}{2}\right ) \left (t^{3}+3 c_{1} +3 t \right )}\right )^{\frac {1}{3}}} \\ y \left (t \right ) &= \frac {\left (i \sqrt {3}-1\right ) \left (27-4 t^{3}-12 c_{1} -12 t +2 \sqrt {4}\, \sqrt {\left (t^{3}+3 t +3 c_{1} -\frac {27}{2}\right ) \left (t^{3}+3 c_{1} +3 t \right )}\right )^{\frac {2}{3}}-9 i \sqrt {3}+6 \left (27-4 t^{3}-12 c_{1} -12 t +2 \sqrt {4}\, \sqrt {\left (t^{3}+3 t +3 c_{1} -\frac {27}{2}\right ) \left (t^{3}+3 c_{1} +3 t \right )}\right )^{\frac {1}{3}}-9}{4 \left (27-4 t^{3}-12 c_{1} -12 t +2 \sqrt {4}\, \sqrt {\left (t^{3}+3 t +3 c_{1} -\frac {27}{2}\right ) \left (t^{3}+3 c_{1} +3 t \right )}\right )^{\frac {1}{3}}} \\ \end{align*}

Solution by Mathematica

Time used: 3.185 (sec). Leaf size: 343

DSolve[y'[t] == (t^2+1)/(3*y[t]-y[t]^2),y[t],t,IncludeSingularSolutions -> True]
 

\begin{align*} y(t)\to \frac {1}{2} \left (\sqrt [3]{-4 t^3+\sqrt {-729+\left (4 t^3+12 t-3 (9+4 c_1)\right ){}^2}-12 t+27+12 c_1}+\frac {9}{\sqrt [3]{-4 t^3+\sqrt {-729+\left (4 t^3+12 t-3 (9+4 c_1)\right ){}^2}-12 t+27+12 c_1}}+3\right ) \\ y(t)\to \frac {1}{4} \left (i \left (\sqrt {3}+i\right ) \sqrt [3]{-4 t^3+\sqrt {-729+\left (4 t^3+12 t-3 (9+4 c_1)\right ){}^2}-12 t+27+12 c_1}-\frac {9 \left (1+i \sqrt {3}\right )}{\sqrt [3]{-4 t^3+\sqrt {-729+\left (4 t^3+12 t-3 (9+4 c_1)\right ){}^2}-12 t+27+12 c_1}}+6\right ) \\ y(t)\to \frac {1}{4} \left (-\left (\left (1+i \sqrt {3}\right ) \sqrt [3]{-4 t^3+\sqrt {-729+\left (4 t^3+12 t-3 (9+4 c_1)\right ){}^2}-12 t+27+12 c_1}\right )+\frac {9 i \left (\sqrt {3}+i\right )}{\sqrt [3]{-4 t^3+\sqrt {-729+\left (4 t^3+12 t-3 (9+4 c_1)\right ){}^2}-12 t+27+12 c_1}}+6\right ) \\ \end{align*}