COS.DAT
Zaimoni: some working notes
These are precomputed cosine values. The complete prime factorization of the file size 5762 is 2·2881.
These should be scaled signed 2-byte integers representing floating-point numbers in the range 0 to 1, scaling factor 210 i.e. 1024. First and last values are identical, so it is simplest to assume there are 2880 distinct reference values here. The intent appears to be to enumerate a full circle.
SIN.DAT is the same format, but holds precomputed sine values.
The following trigonometric identities are satisfied exactly when the period is taken to be 2880, and the indexing units are taken to be eighths of a degree (observe that 2880=360·8):
- half-circle identity
- supplementary function identity
- cofunction identity
- cosine even function, sin odd function identities
Furthermore, the expected nonmonotonic increasing (sine) and nonmonotonic decreasing (cosine) behavior is seen in the raw index range 0..720.
This suggests, but does not allow inducting, that the indexing scheme actually is eighths of a degree.
Whether the Pythagorean identity is approximated correctly has not been verified yet.