I want to enter a mathematical function as an argument to a function

Hello, to be more precise: I want to call in my program a function that I have created and that allows to display the plot of a mathematical function, so I want to enter in argument of this function a mathematical expression that can be for example "sin(t) or 4*t+9". Knowing that the interval "t" is defined inside the function.

My problem is the following, when I launch the program it says to me that it does not know "t", logic since at the moment or the program reads it it is not yet defined.

How to solve this problem?

main program

plot_compare(sin(t) , 5 ,20);

secondary program

function plot_compare(f,N,M)

t = [];
S_N = [];

t = linspace(-pi ,pi ,M);

b = linspace (0,10,N);
S_N = sinesum(t,b);

plot(t,f,t,S_N);

end 

Answer 1

[Stephen23]

The simple approach using a function handle:

plot_compare(@sin , 5 ,20);

plot_compare(@(t) 4*t+9 , 5 ,20);

function plot_compare(fnh,N,M)
t = linspace(-pi ,pi ,M);
b = linspace (0,10,N);
%S_N = sinesum(t,b);
plot(t,fnh(t));
end 

[Paul]

Thank you

I had found the beginning of a solution on the internet with the handle function but I understood where my mistake was, I must specify in the plot function that my function "f" must be plotted as a function of "t" so it's

plot(t,f(t))

and not

plot (t,f)

Thank you again