Clarification/Follow-up by jnlomonte on 01/06/05 8:06 am:
It turns out that my solution was rather serendipitous. The sine of 15 degrees when raised to the eighth power is such a small number, that 97/128 is almost exactly the cosine of 15 degrees raised to the eighth power.

Clarification/Follow-up by jnlomonte on 01/06/05 8:06 am:
It turns out that my solution was rather serendipitous. The sine of 15 degrees when raised to the eighth power is such a small number, that 97/128 is almost exactly the cosine of 15 degrees raised to the eighth power.