Questions tagged [dsolve]
69 questions
1
vote
1 answer
Error in dsolve when variable is multiplied by a constant (R2011a)
I am trying to use the following code:
ode1='D2y1=-1256.4*y1-5*Dy1+255.1*y2+182.781';
ode2='D2y2=-151.5*y2-5*Dy2+255.1*y1-14.0459';
CI='y1(0)=2,y2(0)=-2,Dy1(0)=0,Dy2(0)=0';
sol=dsolve(ode1,ode2,CI,'t');
sol.y1
sol.y2
and matlab returns an…
questioner1234
- 13
- 3
1
vote
1 answer
Cannot transfer variable values into dsolve?
I got one question in matlab:
I get a value of c from other function, then I want to put c value 1 into dsolve to solve this differential equation. but the value cannot put into dsolve, what should I do to transfer value?
eg:
c = 1;
u = dsolve('Du…
user3738476
- 15
- 3
1
vote
1 answer
linear two-equation system, two variables to second derivative in both
Forgive me if this is considered reposting, but I've been advised I might have given a bad format.
I'm trying to solve the two linear, second order differential equations. I want to break them into single order equations, but I can't see how as both…
user2101633
- 11
- 2
0
votes
1 answer
How to solve this Differential Equation without ProductLog in Mathematica?
I'm trying to solve a Differential Equation using Mathematica to check whether the result I get is equal to the result I got by solving the equation by hand.
However, Mathematica gives me an answer including ProductLog which doesn't make sense to…
Cworm
- 1
- 1
0
votes
0 answers
Problem solving differential equation system with dsolve in Matlab
I'm new to Matlab (R2017b). I'm triying to solve a differential equation system with this script:
clear;
syms k x1(t) x2(t) M b f t;
dx2_1 =diff(x2,t);
dx2_2 =diff(x2,t,t);
dx1_1 =diff(x1,t);
dx1_2 =diff(x1,t,t);
eq1 = k*(x1 - x2) - b*dx2_1 ==…
Lucas Marelli
- 1
- 2
0
votes
0 answers
Evaluate symfun at a symbolic variable instead of a number in MATLAB
I created a symbolic function in MATLAB R2021b using this script with the goal of solving an ODE.
syms phi(x) lambda L
eqn_x = diff(phi,x,2) == -lambda*phi;
dphi = diff(phi,x);
cond = [phi(0)==0, dphi(1)==0]; % this is the line where the problem…
WnGatRC456
- 337
- 1
- 2
- 12
0
votes
1 answer
Issue with sympy dsolve and zero
In the following code, I want to have the friction constant 'c' be zero, however, if I put it equal to zero, the dsolve() function hangs up. It works fine if I put it equal to 1e-20 (effectively zero)
I guess using 1e-20 is working but I would like…
KitingPaul
- 49
- 5
0
votes
1 answer
fplot error using second order derivatives / second-order differentiator circuit
d2/dt2i(t) + 25d/dti(t) + 100i(t) = 300
I want to plot x:time, y:i(t) graph using that second-derivative equation
Also I using matlab
syms i(t)
eq = diff(i(t),t,2) + 25*diff(i(t),t) + 100*i(t) == 300;
condition = i(0) == 0 ;
sol(t) = dsolve(eq,…
이승연
- 21
- 1
- 3
0
votes
0 answers
Is there a feature that tells you what hint best to give to the SymPy dsolve function?
I have this ordinary differential equation that I need to solve using SymPy.
The equation: (m, g, C, rho, A are arbitrary constants)
I already managed to get a solution out of it using the code below, but the computation takes more than 2 minutes…
stancallewier
- 11
- 4
0
votes
0 answers
Solving Systems of Linear Homogeneous Ordinary Differential Equations in Sympy
I am trying to solve an ODE of the form: (d/dt) x = A * x
given the square matrix A and the vector x at t=0 in sympy. The system I am studying has more than 50 equations.
As I defined it above, I believe these equations are linear, homogeneous, and…
Daylight
- 1
- 1
0
votes
0 answers
Sympy dsolve is out of memory trying to solve ODE with
I have a second-order linear ODE y'' + (w/c)^2*(cos(cos(2pix/d) + q0)*y=0. I need to get exact and numerical solution. Firstly, i tried to solve it with sympy.dsolve with this code:
c = 1
w = 1.5
d = 1
q0 = 2
wc = (w / c)**2
x = symbols('x')
y =…
Marat
- 1
- 1
0
votes
0 answers
How to simplify a symbolic expression in matlab
I solve a system of differential equations in matlab:
syms x1(t) x2(t) x3(t);
f = 0.5;
u = @(t)(sin(2.5*t + f));
X1 = - 3*x1 + 0.2*x2 + 2*x3 + u;
X2 = -1*x1 - 1.2*x2 + 1.4*x3;
X3 = -0.4*x1 - 0.3*x3;
start_cond = [x1(0) == 0; x2(0) == 0; x3(0) ==…
Vlad
- 1
- 3
0
votes
0 answers
Error when using sympy to solve the Geodesic Equations
I was playing around with General Theory of Relativity, and I was nearly done. But when I use sympy.dsolve to solve the geodesic equations, I always reports "NotImplementedError".
My code look like this:
from gravipy.tensorial import *
from sympy…
Apple Sun
- 33
- 1
- 4
0
votes
2 answers
Sympy dsolve with plots
I am solving an ODE with Sympy. The equation is
ODE
To solve it, I used this little code, which returns this result.
from sympy import *
from numpy import *
import matplotlib.pyplot as plt
x = symbols('x')
y = Function('y')
f =…
J Pablo A
- 3
- 1
0
votes
1 answer
How write the symbolic variable in the sympy EDO dsolve
Good afternoon,
I'm coming here as I noticed something unusual in the results of dsolve() in sympy.
from sympy import *
from sympy.abc import x,y
import sympy as s
import numpy as np
n = symbols('n',…
