ACOS

[dilwyn]

Colin McKay asked me this question, I don't know the answer, can anyone help him? I'll pass on any replies.

I’ve just experienced disruption through using ACOS in a procedure. There were 3 loops which operated as expected, but on the fourth the ACOS caused the message “At line 2345 :1 error in expression”. The line was RR=ACOS(VV). When VV was printed its value was 1, as expected.

I should explain here that when VV was checked by calculator its value was 1.

The error was removed by inserting the line IF VV>1 then : VV=1.

Or by changing the calculation of VV thus: VV=INT((C^2-A^2-B^2)/(-2*A*B)+1E-6).

This implies that when ACOS, or similar, is used the value VV has to be filtered before it is incorporated into ACOS. Is this the practice?

I’ve never done it before.