What kind of integration is this?

[Ballistic]

Homework Statement

I'm given with the following script:

for ii = 2:length(x_time)
    V(ii)                   = V(ii-1) - (forces_x(ii-1)./w) * g .* dt;                                        
    D(ii)                   = 0.5 .* rho .* V(ii).^2 * s * Cd;                    
    R(ii)                   = (not relevant);
    F(ii)                   = 2 .* Cf(ii) .* R(ii);                              
    forces_x(ii)         = (F(ii) + D(ii)) - T(ii);                 
    distance(ii)         = distance(ii-1) + .5 .* (V(ii) + V(ii-1)) .* dt;           
    deceleration(ii)   = (V(ii) - V(ii-1))./dt;                               
end

Homework Equations

Above I've reported only the relevant equations.

The Attempt at a Solution

I'm asked to state what kind of integration is this.

I don't know really how to answer, I was thinking about Euler-method, but right now I am a bit confused.Thank you for your help!

 

[rcgldr]

Two methods are being used, one method for velocity, and another method for distance. Perhaps that is why you're not sure?

 

[Ballistic]

Can you please tell me which is the method for the velocity and which one is for the distance?

Thanks for the help!

 

[rcgldr]

Can you please tell me which is the method for the velocity and which one is for the distance?

Note the key equations being used for velocity and distance are essentially these equations:

v = v[i-1] + a Δt

d = d[i-1] + 1/2 (v + v[i-1]) Δt

 

[Ballistic]

Exactly! Thanks again!

But what's the name (e.g. Runge-Kutta, Euler, ecc.) of this integration methods, if they have any?

 

[rcgldr]

But what's the name (e.g. Runge-Kutta, Euler, ecc.) for these integration methods, if they have any?

These are not Runge-Kutta, at least not the common RK4 version. Don't you have a textbook that explains these methods?

Wiki article:

http://en.wikipedia.org/wiki/Numerical_ordinary_differential_equations

Look for Euler and trapezoidal methods here:

http://en.wikipedia.org/wiki/List_o...l_methods_for_ordinary_differential_equations

 

[Ballistic]

Yessir, I think I was mislead from the homework request.

Thank you for your very accurate answers!