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Engineering Analysis Lab.
- Inverse Laplace
Transform
Created by Omer W. Taha
Computer Engineering Technique
Third Stage
Definition
The Laplace transform is a linear operator
that switched a function f(t) to F(s).
Go from time argument with real input to a
complex angular frequency input which is
complex.
Inverse Laplace Transform
Inverse Laplace Transform
Laplace Transforms with MATLAB
a. Calculate the Laplace Transform using Matlab
Calculating the Laplace F(s) transform of a function f(t) is quite simple in Matlab.
First you need to specify that the variable t and s are symbolic ones. This is done with
the command
>> syms t s
Next you define the function f(t). The actual command to calculate the transform is
>> F=laplace(f,t,s)
To make the expression more readable one can use the commands, simplify and pretty.
here is an example for the function f(t),
f (t)  1.25 3.5te2t
1.25e2t
>> syms t s
>> f=-1.25+3.5*t*exp(-2*t)+1.25*exp(-2*t);
>> F=laplace(f,t,s)
F =
-5/4/s+7/2/(s+2)^2+5/4/(s+2)
>> simplify(F)
ans =
(s-5)/s/(s+2)^2
>> pretty(ans)
s - 5
----------
2
s (s + 2)
which corresponds to F(s),
s(s 2)2
ESE216 5
(s 5)
F(s) 
Alternatively, one can write the function f(t) directly as part of the laplace command:
>>F2=laplace(-1.25+3.5*t*exp(-2*t)+1.25*exp(-2*t))

More Related Content

Inverse Laplace Transform

  • 1. Engineering Analysis Lab. - Inverse Laplace Transform Created by Omer W. Taha Computer Engineering Technique Third Stage
  • 2. Definition The Laplace transform is a linear operator that switched a function f(t) to F(s). Go from time argument with real input to a complex angular frequency input which is complex.
  • 5. Laplace Transforms with MATLAB a. Calculate the Laplace Transform using Matlab Calculating the Laplace F(s) transform of a function f(t) is quite simple in Matlab. First you need to specify that the variable t and s are symbolic ones. This is done with the command >> syms t s Next you define the function f(t). The actual command to calculate the transform is >> F=laplace(f,t,s) To make the expression more readable one can use the commands, simplify and pretty. here is an example for the function f(t), f (t) 1.25 3.5te2t 1.25e2t >> syms t s >> f=-1.25+3.5*t*exp(-2*t)+1.25*exp(-2*t); >> F=laplace(f,t,s) F = -5/4/s+7/2/(s+2)^2+5/4/(s+2) >> simplify(F) ans = (s-5)/s/(s+2)^2 >> pretty(ans) s - 5 ---------- 2 s (s + 2) which corresponds to F(s), s(s 2)2 ESE216 5 (s 5) F(s) Alternatively, one can write the function f(t) directly as part of the laplace command: >>F2=laplace(-1.25+3.5*t*exp(-2*t)+1.25*exp(-2*t))