Hallo Nagarajan,

don't no whether this is what you wanted, but with parabola curve the best fitting coefficents I could get are:

Y = 2001.9 * X -0.003167 * X^2

Deviation from ideal value then is <+-23.

Mayby your problems arise, because precision of calculation is not high enough? I had to switch to double precision, when I calculated coefficients by the help of 'qbasic' program.

Kai