From: Andrew Plotkin (
Date: 23-Feb-95 (21:20:41 GMT)
Subj: the tan idea

Well, it almost works. To wit: we have two examples, both of the form
acos(X) = t; X = p / a; p = b
(where X and p are Cetian symbols, t is an angle, and a and b are numbers.)

In the first example, t=30 deg, a=10, b=11.547068
In the second, t=60 deg, a=5, b=18.

If we regard X and p as variables, the first example is almost correct:
11.547068 / 10 = 1/cos(30), not cos(30). This wouldn't be so much a
tangent problem as a simple find-the-position-of-a-point-on-a-circle.
Except the ratio is upside down and (as everyone has noted) the second
example isn't consistent; 18 / 5 != 1/cos(60).