78 A NEW METHOD OF DETERMINING 
into equations (2), neglecting the mass m, we find 
2, Fe} f 
Ore k?. cos f 2Sey 
a th 7 
@y 4. Wsinf _ y (@) 
dé! pe 
We have also 
= = age 
a) = la joe + reosf. os 
and hence 
ee = es 
or 
eS = ( (Ye — Xy) dt + C; 
and 
ae = f Sr.dt+ ©. 
In the undisturbed motion we have 
Gin —— 
rT). oe =k Py 
po. being the semi-parameter. 
Hence 
Po r= { Sr. dt + kv/ po 
ON Oe 
