Very few modern mathematicians have grasped that sine 75 degrees raised to the power of 10 equals sine 45 degrees. Napier's angles just below 90 degrees are incorrect. The arc sine of 0.9999999 is much closer to 89 39/40 degrees than it is to 89 59/60 degrees. This could explain why nobody seems to have attempted to list the corresponding arc cosines. submitted by Peter L. Griffiths. We can hardly blame school maths when the experts are so negligent.