ode45 say that return column vector using lsqcurvefit

I made 'lsqcurvefit optimization'. The file name is 'sample'. It works well.

And ' (a1 * 2 * f1 * pi * cos(2 * f1 * pi * t))' this formula is about velocity.

 function FF = BF(t, a)
 a1 = 5;
 f1 = 0.5;
 n = 1;

 g = @(t, x)[(a1 * 2 * f1 * pi * cos(2 * f1 * pi * t)); 
       -abs(a1 * 2 * f1 * pi * cos(2 * f1 * pi * t))*a(6)*x(2)*abs(x(2))^(n-1)-a(5)*a1 * 2 * f1 * pi * 
 cos(2 * f1 * pi * t)*abs(x(2))^n+a(4)*a1 * 2 * f1 * pi * cos(2 * f1 * pi * t)];

 [t, xa] = ode45(@(t,x) g(t, x), t, [0 0]);   

 u = a1 * 2 * f1 * pi * cos(2 * f1 * pi * t);

 FF = a(1)*u(:,1)+a(2)*xa(:,1)+a(3)*xa(:,2);
 end

But I got velocity data by a experiment. So i substituted that formula to 'experiment data'.

The file name is sample_2.

I changed something.

First, i removed 'this (a1 * 2 * f1 * pi * cos(2 * f1 * pi * t))'. and i put 'velocity1 [9000x1 vector]'.

Second, i put 'velocity1_int' transposed for making [1x9000 vector].

But, it says '@(X,T)G(X,T) must return a column vector.'

Could you help me about this...

 function FF = BF(velocity1, a, dk1)
 n = 1;
 t = (0:0.0006:5.3994)';

 velocity1_int = velocity1';

 g = @(x,t) [(-abs(velocity1_int)*a(4)*x(1)*abs(x(1))^(n-1)...
    -a(5)*velocity1_int*abs(x(1))^n+a(6)*velocity1_int)];

 [xa] = ode45(@(x,t) g(x,t), t, [0]);   

 FF = a(1)*velocity1+a(2)*dk1+a(3)*xa;

 end

Answer 1

[Torsten]

function FF = BF(velocity1, a, dk1)
 n = 1;
 t_int = (0:0.0006:5.3994)';
 velocity1_int = velocity1';
 [xa] = ode45(@(t_actual,x)g(t_actual,x,a,t_int,velocity1_int), t_int, [0]);   
 FF = a(1)*velocity1+a(2)*dk1+a(3)*xa;
 end

function dx = g(t_actual,x,a,t_int,velocity1_int)
  velocity1_actual = interp1(t_int,velocity1_int,t_actual);
  dx = (-abs(velocity1_actual)*a(4)*x(1)*abs(x(1))^(n-1)...
       -a(5)*velocity1_actual*abs(x(1))^n+a(6)*velocity1_actual);
end

Answer 2

[madhan ravi]

g = @(x,t) [(-abs(velocity1_int)*a(4)*x(1)*abs(x(1))^(n-1);
    -a(5)*velocity1_int*abs(x(1))^n+a(6)*velocity1_int)];

[CHOI HYUNDUK]

Thank you for respoding. But this is one formula not two formulas... So, I need other solution. Thank you so much...