laplace transformation #2

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Hi guys,

I am trying to perform a very simple inverse laplace;
>> syms s
>> f = 1/s;
>> f
 
Transfer function:
1
-
s
 
>> ilaplace(f)

and i am getting this error: _ ??? Undefined function or method 'ilaplace' for input arguments of type 'tf'.

when then tring to do the laplace of another function; i get this error
>>  syms a unreal
t = 0:0.1:10;
y = exp(-a*t);a = 0.25 + j*2*pi;
plot3(t,real(y), imag(y))
grid
>> laplace(y)
??? Undefined function or method 'laplace' for input arguments of type 'double'.

Can anyone please help me out? Thanks beforehand.

A
0
Reply anabelbonello (8) 2/13/2010 12:09:06 PM

See related articles to this posting


"Anabel " <anabelbonello@hotmail.com> wrote in message <hl64p2$iip$1@fred.mathworks.com>...
> Hi guys,
> 
> I am trying to perform a very simple inverse laplace;
> >> syms s
> >> f = 1/s;
> >> f
>  
> Transfer function:
> 1
> -
> s
>  
> >> ilaplace(f)
> 
> and i am getting this error: _ ??? Undefined function or method 'ilaplace' for input arguments of type 'tf'.
> 
> when then tring to do the laplace of another function; i get this error
> >>  syms a unreal
> t = 0:0.1:10;
> y = exp(-a*t);a = 0.25 + j*2*pi;
> plot3(t,real(y), imag(y))
> grid
> >> laplace(y)
> ??? Undefined function or method 'laplace' for input arguments of type 'double'.
> 
> Can anyone please help me out? Thanks beforehand.
> 

Hi Anabel
Do you have the Symbolic Toolbox installed? if you type 

>>ver

at the command prompt, do you find an entry for the Symbolic Toolbox?

Wayne
0
Reply wmkingty (1430) 2/13/2010 12:44:20 PM

HI wayne,

yes there is Symbolic Math Toolbox Version 3.2.2  (R2007b)...dont know what s wrong:S

thanks loads
A




"Wayne King" <wmkingty@gmail.com> wrote in message <hl66r4$sha$1@fred.mathworks.com>...
> "Anabel " <anabelbonello@hotmail.com> wrote in message <hl64p2$iip$1@fred.mathworks.com>...
> > Hi guys,
> > 
> > I am trying to perform a very simple inverse laplace;
> > >> syms s
> > >> f = 1/s;
> > >> f
> >  
> > Transfer function:
> > 1
> > -
> > s
> >  
> > >> ilaplace(f)
> > 
> > and i am getting this error: _ ??? Undefined function or method 'ilaplace' for input arguments of type 'tf'.
> > 
> > when then tring to do the laplace of another function; i get this error
> > >>  syms a unreal
> > t = 0:0.1:10;
> > y = exp(-a*t);a = 0.25 + j*2*pi;
> > plot3(t,real(y), imag(y))
> > grid
> > >> laplace(y)
> > ??? Undefined function or method 'laplace' for input arguments of type 'double'.
> > 
> > Can anyone please help me out? Thanks beforehand.
> > 
> 
> Hi Anabel
> Do you have the Symbolic Toolbox installed? if you type 
> 
> >>ver
> 
> at the command prompt, do you find an entry for the Symbolic Toolbox?
> 
> Wayne
0
Reply anabelbonello (8) 2/13/2010 12:57:05 PM

"Anabel " <anabelbonello@hotmail.com> wrote in message <hl67j1$gbk$1@fred.mathworks.com>...
> HI wayne,
> 
> yes there is Symbolic Math Toolbox Version 3.2.2  (R2007b)...dont know what s wrong:S
> 
> thanks loads
> A
> 
> 
> 
> 
> "Wayne King" <wmkingty@gmail.com> wrote in message <hl66r4$sha$1@fred.mathworks.com>...
> > "Anabel " <anabelbonello@hotmail.com> wrote in message <hl64p2$iip$1@fred.mathworks.com>...
> > > Hi guys,
> > > 
> > > I am trying to perform a very simple inverse laplace;
> > > >> syms s
> > > >> f = 1/s;
> > > >> f
> > >  
> > > Transfer function:
> > > 1
> > > -
> > > s
> > >  
> > > >> ilaplace(f)
> > > 
> > > and i am getting this error: _ ??? Undefined function or method 'ilaplace' for input arguments of type 'tf'.
> > > 
> > > when then tring to do the laplace of another function; i get this error
> > > >>  syms a unreal
> > > t = 0:0.1:10;
> > > y = exp(-a*t);a = 0.25 + j*2*pi;
> > > plot3(t,real(y), imag(y))
> > > grid
> > > >> laplace(y)
> > > ??? Undefined function or method 'laplace' for input arguments of type 'double'.
> > > 
> > > Can anyone please help me out? Thanks beforehand.
> > > 
> > 
> > Hi Anabel
> > Do you have the Symbolic Toolbox installed? if you type 
> > 
> > >>ver
> > 
> > at the command prompt, do you find an entry for the Symbolic Toolbox?
> > 
> > Wayne

Hi Anabel, 

If you type

syms s
f = 1/s;
class(f)
% do you get sym for the class?
% Then 
F = ilaplace(f);
% should return 1

You should be able to copy and paste the above.
Wayne
0
Reply wmkingty (1430) 2/13/2010 1:15:21 PM

Hi,

Thanks loads for the help:) really appreciated it:)

gd day.

A


"Anabel " <anabelbonello@hotmail.com> wrote in message <hl64p2$iip$1@fred.mathworks.com>...
> Hi guys,
> 
> I am trying to perform a very simple inverse laplace;
> >> syms s
> >> f = 1/s;
> >> f
>  
> Transfer function:
> 1
> -
> s
>  
> >> ilaplace(f)
> 
> and i am getting this error: _ ??? Undefined function or method 'ilaplace' for input arguments of type 'tf'.
> 
> when then tring to do the laplace of another function; i get this error
> >>  syms a unreal
> t = 0:0.1:10;
> y = exp(-a*t);a = 0.25 + j*2*pi;
> plot3(t,real(y), imag(y))
> grid
> >> laplace(y)
> ??? Undefined function or method 'laplace' for input arguments of type 'double'.
> 
> Can anyone please help me out? Thanks beforehand.
> 
> A
0
Reply anabelbonello (8) 2/13/2010 1:28:20 PM
comp.soft-sys.matlab 202976 articles. 524 followers. Post

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