EXPLANATION OF SYMBOLS

r!	denotes factorial-r, that is 1 . 2 . 3 . 4 . … (r – 1) . r.
	denotes the binomial coefficient .
[x]	denotes the integral part of x ; more precisely the largest whole number that is not algebraically greater than x ; e.g. = 3 and = – 4.

a = b (mod c) denotes that a – b is a multiple of c.

denotes “is approxipately equal to.”

a < b = c < d denotes : a < b, and b = c ; a < c, but c < d ; a < d.

α < (θ, φ, …) < β denotes α < θ < β, α < ϕ < β, … .

or denotes f(1) + f(2) + f(3) + … + f(k).

or denotes f(1) . f(2) . f(3) . … f(k).

increases steadily is taken to mean “always increases or at any rate does not decrease.”

E.T. Elementary Trigonometry, by C. V. Durell and H. M. Wright.

M.G. Modern Geometry, by C. V. Durell.