\( \DeclareMathOperator{\abs}{abs} \)
(%i12) laplace(3,t,s);
\[\mathrm{\tt (\%o12) }\quad \frac{3}{s}\]
-->
(%i13) ilt(%, s, t);
\[\mathrm{\tt (\%o13) }\quad 3\]
(%i1) exp(-6*t)*sin(4*t)+exp(-6*t)*cos(4*t);
\[\mathrm{\tt (\%o1) }\quad {{e}^{-6\cdot t}}\cdot \mathrm{sin}\left( 4\cdot t\right) +{{e}^{-6\cdot t}}\cdot \mathrm{cos}\left( 4\cdot t\right) \]
(%i2) laplace(%,t,s);
\[\mathrm{\tt (\%o2) }\quad \frac{6+s}{{{s}^{2}}+12\cdot s+52}+\frac{4}{{{s}^{2}}+12\cdot s+52}\]
(%i3) ratsimp(%);
\[\mathrm{\tt (\%o3) }\quad \frac{10+s}{{{s}^{2}}+12\cdot s+52} = \frac{s + 10}{(s+6)^2 + 16}\] Siste formen er på mathlabplus sin foretrukne form.
ex01.png
(%i2) ( (54/s^4)  -  (12/s^3)  +  (4/s^2) );
ilt(%,s,t);
\[\mathrm{\tt (\%o1) }\quad \frac{4}{{{s}^{2}}}-\frac{12}{{{s}^{3}}}+\frac{54}{{{s}^{4}}}\]\[\mathrm{\tt (\%o2) }\quad 9\cdot {{t}^{3}}-6\cdot {{t}^{2}}+4\cdot t\] ex01_a.png

Inverse laplace:

Find the inverse Laplace transform of: \[\mathrm{}\quad \frac{s + 10}{(s+6)^2 + 16}\]
(%i1) ilt(((s+10)/expand(((s+6)^2)+16)),s,t);
\[\mathrm{\tt (\%o1) }\quad {{e}^{-6\cdot t}}\cdot \left( \mathrm{sin}\left( 4\cdot t\right) +\mathrm{cos}\left( 4\cdot t\right) \right) \] \[\mathrm{}\quad \mathcal{L}^{-1} \{\frac{s + 10}{(s+6)^2 + 16}\} = \mathcal{e}^{-6t}\mathrm{sin}\ 4t+\mathcal{e}^{-6t}+\mathrm{cos}\ 4t\]
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