Second Order ODE Error (Error in ode45 (line 115))

Despite my best attempts to debug this small bit of code, I can't seem to find a solution for the error that I am receiving.

Are my ode45 parameters in the wrong form?

This is all one file:

clear all
%-----------------------------
xo = [1; 0.1];
tspan = [0 20];
[t,x]=ode45('f',tspan,xo);
plot(t,x(:,1));
%-----------------------------
function v = f(t,x)
m = 10; k = 25; 
alpha = 250; 
Fo = 150; 
w = sqrt(k/m); 
ceq = sqrt(q*m*alpha*Fo/m/3/pi);
v =[x(2); x(1).*-k/m+ x(2).*-ceq/m + Fo/m*cos(w*t)];
end
%-----------------------------

Errors Output:

Error in ode45 (line 115)

odearguments(FcnHandlesUsed, solver_name, ode, tspan, y0, options, varargin);

Error in Chase_Harmon_HW_6_ME_3220_003_Extra_Credit_Problem_3 (line 5)

[t,x]=ode45('v',tspan,xo);

Answer 1

[KALYAN ACHARJYA]

In the function file following line q is not defined

ceq = sqrt(q*m*alpha*Fo/m/3/pi);

[Chase Harmon]

I can't believe I missed that, it's supposed to be just 8...

Thank you so much! It worked.

[KALYAN ACHARJYA]

Welcome!