4.8.3 Laplace Transforms

We illustrate Laplace transforms:
sage: _ = maxima.eval("f(t) := t*sin(t)")
sage: maxima("laplace(f(t),t,s)")
2*s/(s^2 + 1)^2

sage: maxima("laplace(delta(t-3),t,s)") #Dirac delta function
%e^-(3*s)

sage: _ = maxima.eval("f(t) := exp(t)*sin(t)")
sage: maxima("laplace(f(t),t,s)")
1/(s^2 - 2*s + 2)

sage: _ = maxima.eval("f(t) := t^5*exp(t)*sin(t)")
sage: maxima("laplace(f(t),t,s)")
360*(2*s - 2)/(s^2 - 2*s + 2)^4 - 480*(2*s - 2)^3/(s^2 - 2*s + 2)^5 +
120*(2*s - 2)^5/(s^2 - 2*s + 2)^6
sage: maxima("laplace(f(t),t,s)").display2d()
                                         3                 5
           360 (2 s - 2)    480 (2 s - 2)     120 (2 s - 2)
          --------------- - --------------- + ---------------
            2           4     2           5     2           6
          (s  - 2 s + 2)    (s  - 2 s + 2)    (s  - 2 s + 2)

sage: maxima("laplace(diff(x(t),t),t,s)")
s*laplace(x(t),t,s) - x(0)

sage: maxima("laplace(diff(x(t),t,2),t,s)")
-at('diff(x(t),t,1),t = 0) + s^2*laplace(x(t),t,s) - x(0)*s

It is difficult to read some of these without the 2d representation:

sage: maxima("laplace(diff(x(t),t,2),t,s)").display2d()
                     !
            d        !         2
          - -- (x(t))!      + s  laplace(x(t), t, s) - x(0) s
            dt       !
                     !t = 0

Even better, use view(maxima("laplace(diff(x(t),t,2),t,s)")) to see a typeset version.

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