How to check the complementary time-dependent term of differential equations.

https://jp.mathworks.com/matlabcentral/answers/99007-

Is there any way to check how the time-dependent term ft in the following code is completed by interp1?

function [T1,Y1] = ode_param_sample1()   
TSPAN = [0 pi/2]; 
IC = 1;   
tv = linspace(0,pi/2,10);
ftv = sin(tv);   
[T1 Y1] = ode45(@myODE1, TSPAN, IC); 
    
     function dydt1 = myODE1(t1,y1) 
        ft = interp1(tv, ftv, t1,'spline');
        dydt1 = - ft *y1;                   
     end 
end

I want to check the ft in this code.

By checking, I mean I want to compare it with the original time-variant parameters, such as plotting it on a graph.

Answer 1

[SALAH ALRABEEI]

    % Try this
function [T1,Y1] = ode_param_sample1()   
TSPAN = [0 pi/2]; 
IC = 1;   
tv = linspace(0,pi/2,10);
ftv = sin(tv);   
ft = interp1(tv, ftv, T1,'spline');
plot(tv,ftv,'or',T1,ft,'b')

[CT]

I tried, but I couldn't.

I get the message "The function or variable 'T1' is not recognized."