Plate Theory and Extensions - The Position of the Points of Inflection > Page 57
Substituting for from equation (51) in equation (50),
Now, Consequently, the term and those
higher can be ignored with respect to .
Then, and (52)
Equation (52) shows that the points of inflection occur at 0.6065 of the peak height. It follows that the peak width, at 0.6065 of the peak height, will be equivalent to two standard deviations (2s) of the Poisson or Gaussian curve.