dF t^2 d^2F
F' = F + t-- + --- ---- + ...
dt 1.2 dt^2
t^2
= F + tX.F + --- X.X.F + ...
1.2
It must, of course, be understood that in this analytical
representation of the effect of the finite operation on F it is
implied that t is taken sufficiently small to ensure the convergence
of the (in general) infinite series.