Encyclopaedia Britannica, 11th Edition, "Baconthorpe" to "Bankruptcy" / Volume 3, Part 1, Slice 2

by Various

from which y/x can be calculated, and thence y.

In the application of Siacci's method to the calculation of a trajectory in high angle fire by successive arcs of small curvature, starting at the beginning of an arc at an angle φ with velocity v_φ, the curvature of the arc φ - θ is first settled upon, and now

(80) η = ½(φ + θ)

is a good first approximation for η.

Now calculate the pseudo-velocity u_φ from

(81) u_φ = v_φ cos φ sec η,

and then, from the given values of φ and θ, calculate u_θ from either of the formulae of (72) or (73):—

(82) I(uθ) = I(uφ) -	tan φ - tan θ	,
	C sec η

(83) D(uθ) = D(uφ) -	φ° - θ°	.
	C cos η

Then with the suffix notation to denote the beginning and end of the arc φ - θ,