How to say that a constant is not a variable?

Hi,

I would like to solve an ode in a analytic way

So i do:

df= @(,) ...
syms T(t)
df1=sym(df);
y0=10 % a constant
f_exact = matlabFunction(dsolve(diff(T,1) == df1 , T(0)== y0));

If I run that i am getting f_exact=@(t,y0) ... % function of t and y0

How wan i do to say that y0 is a constant

Thank you

[Walter Roberson]

Could you give us df itself to test with?

[Quentin Dragomir]

df = @(t,T) -0.1*(T -10);

df1= 1 - T/10

If I do

f_e = matlabFunction(dsolve(diff(T,1) == -0.1*(T-10),T(0) == 100)) It works, but i need a dynamic code so I can't write it

Answer 1

[Walter Roberson]

When you do

df = @(t,T) -0.1*(T -10);

then the T is taken from the second argument of df, not from the syms T(t). When you sym(df) then the T that appears in the result is a different T, not the same one as syms T(t) .

Instead of using

df1 = sym(df)

you should be using

syms T(t)
df1 = df(t,T)

[Quentin Dragomir]

Thank you! It works