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Results tagged with Search options user 58104
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Questions on the symbolic (DSolve, DifferentialRoot) and numerical (NDSolve) solutions of differential equations in Mathematica.

Look at https://reference.wolfram.com/language/ref/NDSolveValue.html in Possible issues/Multiple Solutions. They are indeed saying that NDSolveValue can't make it. There are two possible differential …
answered Nov 23 '18 by J.A
I have a question please. I have an issue with my code while trying to solve an equation. Here it is : sol = Block[{\[Epsilon] = $MachineEpsilon}, NDSolve[{Div[(f[x])*(1 - f[x])*Grad[(-2 f[x] + 4*f[x … asked May 14 '18 by J.A 1answer I'm getting crazy with this Manipulate : Clear[l, L, nc, phic, tauC, tauG, tauS, phi0, Vinitphi, Vphi0, nL0, \ V, Vphi, VinitR, VinitR0, dV, V0, Vphi0] VinitR0 = 0 L = 6000 nL0 = 1 phi0 = 0.4 mode … asked Jun 14 by J.A 1answer I have an equation that I solve : sol = NDSolve[{ Div[(1 - f[x]) Grad[f[x], {x, y}, "Polar"], {x, y}, "Polar"] == -(1 - f[x]) f[x] (f[x] - 0.8), f[1] == 0.7, f'[0.00001] == 0.0001}, f, {x, 0.000 … asked Jun 11 '18 by J.A 0answers I'm working on differential equations and I first used a potential without Piecewise. But given that I wanted to constrain the values between 0 and 1, I started to use Piecewise in the potential, maki … asked May 22 '18 by J.A 0answers I'm trying to solve the following differential equation with some specific conditions NDSolve[{2 V[X] - 2 X Derivative[1][V][X] - X^2 V[X] Derivative[1][V][X] + 4 X^3 V[X] Derivative[1][V][X] - X … asked Nov 5 '18 by J.A 1answer Is it possible to make a parametric ItoProcess ? I'd like to write that equation : V0 = 1 a = 0.1 i0[Vt0_] = ItoProcess[\[DifferentialD]V[t] == a*Plus[UnitStep[V0 - V[t]] V[ t]*\[DifferentialD]t … asked Apr 11 by J.A 2answers I'd like to plot the maximum of a curve in function of a parameter. Meaning I looking for maxima that depend on a parameter. Here is what I tried to do but FindMaximum is not parametric, so it did no … asked May 9 by J.A So I eventually used Table, which allows a "manual parametrization" : a = 1/2 F[x_, y_, z_] = (1 + a*y)*x^2*z^2 - b*x*y mux[x, y, z] = D[F[x, y, z], x] muy[x, y, z] = D[F[x, y, z], y] muz[x, y, z] = … answered May 10 by J.A 0answers I'm trying to write a stochastic differential equation, using ParametricNDSolve and WhenEvents : s = ParametricNDSolve[{V'[t] == Piecewise[{{(a + mu[t])*V[t], V[t] < V0}, {(a + mu[t])*V[t]^(2/3 … asked Apr 11 by J.A 0answers So I have a quite complicated ParametricNDSolve : taustart=5; epsilon=0.0001; v=600; L=1000; D0=9*10^4; nR=1; sol = ParametricNDSolve[ {R'[ t] == (D0 E^(-((L - t v)^2/(4 D0 t))) (L + t v))/( … asked Jul 24 by J.A 1answer I would like to implement a sort of Euler explicit manually. I have this code alpha=1 a = 9/4 SOL[R_] = NDSolveValue[{-alpha * (-2 + 12*a*f[x]^2)*Laplacian[f[x], {x, y, z}, "Spherical"] == (Ma … asked Jun 13 '18 by J.A 1answer I'm trying to solve the heat/diffusion equation in 3d in spherical symmetry$\partial_t f=D\Delta f\$. I wrote : DSolve[{D[f[x, t], t] == Laplacian[f[x, t], {x, y, z}, "Spherical"],f[R,t]==C0,f[Infini …