Solving a nonlinear equation numerically
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I want to solve the nonlinear equation d^2(x)/dt^2 +(k)sinx = 0, numerically.
alternatively, this can be written as
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Answers (1)
John D'Errico
on 29 Oct 2020
It looks as if you don't need to solve it numerically.
syms x(t)
xpp = diff(x,t,2)
syms k
dsolve(xpp + k*sin(x) == 0)
dsolve(xpp + k*sin(x) == 0)
ans =
0
2*jacobiAM((2^(1/2)*(C1 - k)^(1/2)*(C2 - t)*1i)/2, -(2*k)/(C1 - k))
-2*jacobiAM((2^(1/2)*(C1 - k)^(1/2)*(C2 - t)*1i)/2, -(2*k)/(C1 - k))
Of course, it would help if you had some initial or boundary conditions. Then you might get a better answer.
But if you really, really need to solve it numerically, then you need to start with a tool like ODE45, and you need to pose a set of initial conditions, etc. As well, you need to define the value of k. No numerical solution can be found unless you specify k as a NUMBER.
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