Numerically
integrates user's data given in columns in a text-style file
(such as a '.csv' file). It is assumed that: the 1.st column contains
the independent variable, X, with equally spaced values;
and the 2.nd column contains the dependent variable, Yk,
with k = 1..m, the column to be integrated.
(More columns can be given, 'kol' ≥ 2 being used.)
Iff Δx = 0, the 1.st column is read to compute
the true value.
The integration is done by the trapezoid or by the Simpson's
rule.
An example 'csv' user file is given
here (giving 110.555 trap., 110.5502 Simp.)
or here.
[The decimal mark can be point ("international") or
comma ("European").]
("% Error:" messages: 2, file too large; 4, no file uploaded.)
Plots the given yk and
the numerical integral Yk vs
the abscissa k = 1..m.
Other suggested data: other columns (3–5)
of the example file). | 
