Hi all,
I'm embarrassed to have to ask this, but if I have two points
x1 +/- sx1
y1 +/- sy1
and
x2 +/- sx2
y2 +/- sy2
where sx1 is sigma for the Cartesian coordinate x of the first point,
and so on,
what is sigma for r = sqrt( (x2-x1)**2 + (y2-y1)**2 ) ?
Patrick Wallace
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