# How to take laplace transform of square(t) function

11 visualizaciones (últimos 30 días)
Michael Mulumba el 13 de Abr. de 2015
Comentada: laisha el 13 de Sept. de 2016
I am currently on part b. I believe the problem is asking me to generate the square wave, which I do through square(t) from 0 to 30. But when I take the laplace transform I get an error.
syms s j Y;
f=square(j);
F=laplace(f,j,s)
-----------------------------------
Input arguments must be 'double'.
I can generate the wave but then I can't use the laplace transform. I've tried generating the square wave by using sin(t)/abs(sin(t)) but I don't know how to use the output of that function either.
Using this video and this pdf I believe the laplace transform is (exp(-s*pi) - 1)/(s*(exp(-s*pi) + 1) but I cannot replicate this in matlab.
What is the best way to generate this wave and obtain its laplace transform, should I just try to do the steps the same as in the video and ignore the laplace function or am I missing something?
##### 1 comentarioMostrar -1 comentarios más antiguosOcultar -1 comentarios más antiguos
RahulTandon el 7 de Jul. de 2015
Editada: Image Analyst el 15 de Jul. de 2015

do you mind asimulink solution to the problem?

Iniciar sesión para comentar.

### Respuestas (1)

Philip Caplan el 15 de Abr. de 2015
Editada: Philip Caplan el 15 de Abr. de 2015
Since this is a homework problem, I'll only give some hints. The reason you are getting the error message "Input arguments must be 'double'" is because "square" is not defined for symbolic inputs. However, from your homework question, note that "h(t) is defined on [0,10*pi]" which can be described by:
syms t
n = 10;
h = heaviside(t);
for i=1:n
h = h +2*((-1)^i)*heaviside(t -i*pi);
end
You can then call "laplace(h)" but note this is only a part of the full square wave, defined on [0,10*pi]. Hope this helps.
##### 1 comentarioMostrar -1 comentarios más antiguosOcultar -1 comentarios más antiguos
laisha el 13 de Sept. de 2016
If i want n equals to infinity, what changes should i make? The function gives an error

Iniciar sesión para comentar.

### Categorías

Más información sobre Ordinary Differential Equations en Help Center y File Exchange.

### Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by