According to the the acos_fr16, acos_fr32, acos_fx16 and acos_fx32 functions are defined for fractional input values between 0 and 0.9. I have verified experimentally that this is indeed the case.,
My question is therefore: how can I compute acos(x) for x=[0.9;1] without resorting to floating-point functions (or a LUT)?
As far as I know, there is no simple trigonometric identity or symmetry property that allows one to compute this from the available interval.
Thank you for the help!