An introduction to mathematics, by A. N. Whitehead.

SERIES 915
corresponding function is vitally important
to the theory of statistics, and tells us in
many cases the sort of deviations from the
average results which we are to expect.
Another important function is found by
combining the exponential function with the
sine, in this way:
y = exp(- cx) X sin -
ye oP
J-\. C..E F
Fig. 31.
Its graph is given in fig. 31. The points
A, B, O, C, D, E, F, are placed at equal intervals ip, and an unending series of them
should be drawn forwards and backwards.
This function represents the dying away of
vibrations under the influence of friction or of
"damping" forces. Apart from the friction,
the vibrations would be periodic, with a
period p; but the influence of the friction