how to lapace results

how to plot this please

deqdiff = 'diff(y(t),t,t) + y(t) - cos(t)'
ldeqdiff = laplace(deqdiff,t,s)
sldeqdiff = subs(ldeqdiff,{'D(y)(0)','y(0)'},{1,1})
syms Ys
ldeqinit = subs(sldeqdiff,'laplace(y(t),t,s)',Ys)
ly = solve(ldeqinit,Ys)
ilaplace(ly,s,t)

Answer 1

[Walter Roberson]

syms s t y(t)
Dy = diff(y);
deqdiff = diff(y(t),t,t) + y(t) - cos(t);
ldeqdiff = laplace(deqdiff,t,s);
sldeqdiff = subs(ldeqdiff,{Dy(0), y(0)},{1,1});
syms Ys
Lyt = laplace(y(t), t, s);
ldeqinit = subs(sldeqdiff, Lyt, Ys);
ly = solve(ldeqinit,Ys);
ily = ilaplace(ly,s,t);
fplot(ily, [0 20])

[madhan ravi]

+1 , I was thinking too much but it was so simple , thank you sir Walter

[Brenda Galabe]

syms s t y(t)
dy = diff(y);
deqdiff = 'diff(y(t),t,t) + y(t) - cos(t)'
ldeqdiff = laplace(deqdiff,t,s)
sldeqdiff = subs(ldeqdiff,{'D(y)(0)','y(0)'},{1,1})
syms Ys
Lyt = laplace(y(t), t,s );
ldeqinit = subs(sldeqdiff,Lyt,Ys);
ly = solve(ldeqinit,Ys);
ily = ilaplace(ly,s,t)
fplot(ily,[0 20])

getting error :

Error using fcnchk (line 106)
If FUN is a MATLAB object, it must have an feval
method.

Error in fplot (line 62)
   fun = fcnchk(fun);

[Walter Roberson]

You are using the transition release, when fplot had been introduced but did not yet support symbolic expressions.

Replace

fplot(ily,[0 20])

with

Fily = matlabFunction(ily);
fplot(Fily, [0 20])

.... And laplace still is not documented in your release (or any other release) as accepting a character vector. You need to start using documented behaviour or else we are going to start telling you to work things out by yourself since you are relying on undocumented behaviour.

[Brenda Galabe]

thank you that worked