jrjohansson / numerical-python-book-code

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laplace transform of diffrential equation with integral #4

Open machine85 opened 5 years ago

machine85 commented 5 years ago

Hello, i saw your great function for "Evaluate the laplace transforms of derivatives of functions":

' ' ' def laplace_transform_derivatives(e): """ Evaluate the laplace transforms of derivatives of functions """ if isinstance(e, sympy.LaplaceTransform): if isinstance(e.args[0], sympy.Derivative): d, t, s = e.args n = d.args[1][1] return ((s*n) sympy.LaplaceTransform(d.args[0], t, s) - sum([s*(n-i) sympy.diff(d.args[0], t, i-1).subs(t, 0) for i in range(1, n+1)]))

if isinstance(e, (sympy.Add, sympy.Mul)):
    t = type(e)
    return t(*[laplace_transform_derivatives(arg) for arg in e.args])

return e

' ' ' how to solve diffrential equation with integral ? example: dy/dt-2y(t)=0.2(1-y(t))+0.1∫(1-y(t))dt

regarsd, Tomer