Look bird brain John Gabriel birdbrain, the
difference between your aux and MVT is extremely trivial,
and to see that we can use Geogebra which has autodiff.
First in your videos everybody sees that you program
Geogebra as follows (the below is not exactly a
screenshot from your Geogebra, but the idea is clear):
aux(x,m,n) := (f(x+n)-f(x-m))/(m+n) - f'(x)
/* in Geogebra CAS you can automatically let do the
computer the job of calculating f'(x) symbolically
from f(x). */
Now since years you are bugging everybody with this
is the new calculoose and you are doing all tricks,
like solving aux from x,m for n etc..
Which has nothing to do with the MVT. In the MVT
we have two points x and c. And we have what we
might call the extended aux:
aux(x,m,n,c) = (f(x+n)-f(x-m))/(m+n) - f'(c)
/* in Geogebra CAS gain I guess you could automatically
let do the computer the job of calculating f'(c)
symbolically from f(x). You need an extra step
substituting c for x. */
Now the MVT states: There exists a c for a given x,m,n,
such that aux(x,m,n,c)=0. So we have totally different
solution input/output patterns:
JGs aux: Result is some interval bound,
Input x,m
Output n
MVT: Result is some point inbetween,
Input x,m,n
Output c
Of couse in the above MVT we could also go only with
two parameters b=x+n and a=x-m, since then b-a=n+m.
This is the normal casting of MVT.
But so far I don't see any article or video of JG
where you get the MVT correctly. If if you sometimes
cite the MVT from Wiki, in the end you always make
a great mess.