result of acosh is never more precise than double

20 largest ulp errors (stored in a double)
   1.50482 ulp for acosh(1.2603620027999882) = 0.70680725893044993)
   1.50330 ulp for acosh(1.4256143562999894) = 0.89268368691293798)
   1.50033 ulp for acosh(1.1053530086000076) = 0.45508989593357241)
   1.50010 ulp for acosh(1.3633073696997648) = 0.82851594404930373)
   1.50002 ulp for acosh(1.2603620028001832) = 0.70680725893070373)
   1.50001 ulp for acosh(1.2867231360025231) = 0.74024509476679057)
   1.50000 ulp for acosh(1.3633073697067835) = 0.82851594405687856)
   1.50000 ulp for acosh(1.1053530085964369) = 0.4550898959259907)
   1.49996 ulp for acosh(1.0807728334848301) = 0.39927005566131807)
   1.49995 ulp for acosh(1.2600608981000938) = 0.70641463224198719)
   1.49989 ulp for acosh(1.0075487162999484) = 0.12279444763620369)
   1.49770 ulp for acosh(1.0075487162891357) = 0.12279444754836943)
   1.49127 ulp for acosh(1.0075487162999883) = 0.12279444763652836)
   1.48954 ulp for acosh(1.0075487162999963) = 0.12279444763659329)
   1.47978 ulp for acosh(1.2600608980999979) = 0.70641463224186207)
   1.47233 ulp for acosh(1.5240788612999996) = 0.98365640570530721)
   1.33774 ulp for acosh(1.1053530086000023) = 0.45508989593356125)
   1.00034 ulp for acosh(1.0078226778256265) = 0.12499999999932698)
   0.99606 ulp for acosh(1.0078226778111077) = 0.12499999988347824)
   0.91277 ulp for acosh(1.0314130998795727) = 0.24999999999999828)

<tr><td align=left><a href=acosh.res>acosh</a></td><td align=right>1033</td><td align=right>1.50482</td><td>1.2603620027999882</td><td>0.70680725893044993</td></tr>