Replacing Variable in an ODE

syms T(t)
ode = diff(T,t) == (Lemda-(Sigma.*T));
cond = T(0) == To;
Solution = dsolve(ode, cond)

ERRORS; (Not replacing with a variable)

Undefined function or variable 'Lemda'.

Error in Project (line 11)

ode = diff(T,t) == (Lemda-(Sigma.*T));

[SALAH ALRABEEI]

Are Lamda and sigma constants or vaiables!

[Walter Roberson]

It does not matter. dsolve() is for symbolic expressions, so we can create symbolic variables without caring about whether they will later be constants or later will be changed.

[Fahad Ramzan]

Yeah!

[SALAH ALRABEEI]

Thanks Walter.

Answer 1

[Walter Roberson]

syms T(t) Lemda Sigma To
ode = diff(T,t) == (Lemda-(Sigma.*T));
cond = T(0) == To;
Solution = dsolve(ode, cond)

Solution = 

[Fahad Ramzan]

Are these answers the same? Because the solution goes this way where i made assumptions as following

%Assumptions

% Lemda = constant input source of uninfected cells per day

% Sigma = normal loss rate constant of uninfected cells

% Beta = infection rate constant of uninfected cells per infected cell

% Mu = loss rate constant of infected cells

% Gamma = loss rate constant of free virus

% N = number of virions produced per day per infected cell