cpyles1
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I've been trying to solve this one for a while. My professor wasn't even sure how to do it. Any suggestions?
y''+t*y+y*y'=sin(t)
y''+t*y+y*y'=sin(t)
The discussion focuses on solving the second-order nonlinear differential equation y'' + t*y + y*y' = sin(t). A power series solution is proposed, along with Mathematica code to implement the solution. The code includes the use of summations to derive coefficients and plots the results using NDSolve for numerical solutions. The provided Mathematica code effectively demonstrates how to approach this complex differential equation.
PREREQUISITESMathematics students, researchers in applied mathematics, and anyone interested in solving complex differential equations using computational tools like Mathematica.
cpyles1 said:I've been trying to solve this one for a while. My professor wasn't even sure how to do it. Any suggestions?
y''+t*y+y*y'=sin(t)
Remove[a];
nmax = 25;
myleftside = Sum[n*(n - 1)*Subscript[a, n]*t^(n - 2), {n, 0, nmax}] +
Sum[Subscript[a, n - 3]*t^(n - 2), {n, 3, nmax + 2}] +
Sum[Subscript[a, k]*Subscript[a, n - k]*(n - k)*t^(n - 1), {n, 0, nmax + 1}, {k, 0, n}];
myrightside = Sum[((-1)^n*t^(2*n + 1))/(2*n + 1)!, {n, 0, nmax}];
myclist = Flatten[Table[Solve[Coefficient[myleftside, t, n] == Coefficient[myrightside, t, n],
Subscript[a, n + 2]], {n, 0, nmax}]];
Subscript[a, 0] = 0;
Subscript[a, 1] = 1;
mysec = Table[Subscript[a, n] = Subscript[a, n] /. myclist, {n, 2, nmax}];
thef[t_] := Sum[Subscript[a, n]*t^n, {n, 0, nmax}];
p1 = Plot[thef[t], {t, 0, 2}, PlotStyle -> Red];
mysol = NDSolve[{Derivative[2][y][t] + t*y[t] + y[t]*Derivative[1][y][t] == Sin[t], y[0] == 0,
Derivative[1][y][0] == 1}, y, {t, 0, 2}];
p2 = Plot[y[t] /. mysol, {t, 0, 2}, PlotStyle -> Blue];
Show[{p1, p2}]