Help clearing up "Unrecognized function or variable 'dt'."

%% Problem 2 Linear Actuator
t0=0;
tf=0.1;
ft=0.001;
tspan=[t0:dt:tf]; %This is where I'm getting the error "Error in ProgramName(line 49)tspan=[t0:dt:tf];Unrecognized function or variable 'dt'."
x0=0;
xdot0=0;
i0=0;
IC=[x0 xdot0 0];
[t,z]=ode45(@actuator_ode,tspan,IC,[]);
x=z(:,1);
curr=z(:,3);
subplot(2,1,1)
plot(t,curr)
subplot(2,1,2)
plot(t,x)

Answer 1

[Cris LaPierre]

Based on the code you've shared, and the error message you are getting, you have not defined the variable dt that you are using to create tspan. You need to either replace dt with a numeric value, or first define dt.

tspan=[t0:0.1:tf];

% or
dt = 0.1;
tspan=[t0:dt:tf];

[Jan]

t0:dt:tf is a vector already. There is no need to include it in Matlab's operator [] for concatenating arrays.