help with function loop

So I'm having trouble with the loop portion of my function. when I try multiplying my v(n) by t I get an error that's there's a different number of elements on either side of my function. I don't quite see what I need to fix. Any help would be appreciated, thanks.

function [v,x,t,FD] = EDDO(N,dt,wd,k,b,f,F,m,x0,v0,t0)

x=zeros(N,1); % Preallocate position array
v=zeros(N,1); % Preallocate velocity array
t=zeros(N,1); % Preallocate time array
FD=zeros(N,1); % Preallocate array for driving force values

x(1)=x0; % Set initial condition for position in m
v(1)=v0; % Set initial condition for velocity in m/s
t(1)=t0; % Set initial time in s.
FD(1)=F*cos(wd*t(1)); % Calculate initial force value


for n=1:N % Set the number of loops  
    v(n+1)=v(n); % calculate next velocity
    x(n+1)=x(n)+v(n); % calculate next position
    t(n+1)=t(n); % calculate next time value
    FD(n+1)=FD(n); % calculate next driving force value
end

end

[Walter Roberson]

I do not see any multiplication other than the initial force value ?

What are size(F), size(wd) ?

    t(n+1)=t(n); % calculate next time value

That is likely to be wrong. Next time value would be at a later time: time should be increasing.

    FD(n+1)=FD(n); % calculate next driving force value

Maybe. But I would tend to suspect that the driving force is intended to change as time changes, F*cos(wd*t(n)) or F*cos(wd*t(n+1)) or perhaps the mean of those two.