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= (ayn! + ex? — y? id) + = +e) (2 —y)= 0 
By this and the first equation the constants e and f being elimi- _ 
nated, we find 
ry dy + dy (ady — ydr) = 0 
Dividing this by a* it becomes 
y Yay ae a i & 
Let s = 4 dg= an. Hae By this substitution the equation 
becomes 
ad’y + dydz = 0 
. by de 
dy + fe 
This being integrated gives 
zdy = Mdz 
m being an arbitrary constant. Substituting for z its value, the 
equation becomes 
ydy =Madx. 
The integral of this is evidently 
y =M2’+n 
n being a second arbitrary constant. This is the equation of an 
