calculating maximum error

I created an vector in matlab that represents an object moving at a velocity v(t) = 5 + 7*t^2 starting from the position x(2) = 5 at t = 2. This vector is called x and is: x2 + 5*t + 7*t.^3/3 (x2 equals 5) (this vector was solved analytically, i.e. I just integrated the velocity function. The next vector, called xtrap, was created using MATLAB's cumtrapz function: xtrap = cumtrapz(t,v) + x2.

How do I calculate the maximum error between these two solutions? Thanks.

Answer 1

[Wayne King]

   max(abs(x-xtrap))

If you want to know which index in the vector was the largest difference

    [maxdiff,Index] = max(abs(x-xtrap));

Another way is

 norm(x-xtrap,Inf)

but that way, you don't get the index

[Jonathan]

Thanks! This is very helpful.

[Mounir guesbaya]

Thank you.