d^2[phi]
(13) A -------- sin [gamma] - (K[mu] + gMh) sin [theta] cos [phi] = 0,
dt^2
so that [phi] = 1/2[pi] gives the position of stable equilibrium, and
the period of a small oscillation is 2[pi] [root]{A sin [gamma]/(K[mu] +
gMh) sin [theta]}.
In the general case, denoting the periods of vibration about [phi] =
1/2[pi], -1/2[pi], and the sidelong position of equilibrium by
2[pi]/(n1, n2, or n3), we shall find
sin [theta]
(14) n1^2 = ------------- {gMh + K[mu] - A[mu]^2 cos ([gamma] - [theta])},
A sin [gamma]
sin [theta]
(15) n2^2 = ------------- {-gMh - K[mu] + A[mu]^2 cos ([gamma] + [theta])},
A sin [gamma]
(16) n3 = n1 n2/[mu] sin [theta].