From: "Földes László" <lists@...>
Date: 2012-04-11T00:37:18+09:00
Subject: BigDecimal precision on square root

What is the problem with this?:

> BigDecimal("4").sqrt(10)
=> #<BigDecimal:9c5a734,'0.1999999999 9999999998 66602351E1',36(36)>
> BigDecimal("4").sqrt(11)
=> #<BigDecimal:9c6457c,'0.2E1',9(45)>

`sqrt`'s parameter should be the precision, and for this operation 4
should suffice (or not?). Documentation on BigDecimal.sqrt is a tad bit
suboptimal, it states that `n` for `sqrt(n)` is optional, however it is
a must.

> BigDecimal("4").sqrt
ArgumentError: wrong number of arguments(0 for 1)
from (pry):35:in `sqrt'

Why BigDecimal.sqrt is imprecise and why do I have to set a 11 digit
precision to get the proper value for sqrt(4)?

-- 
Posted via http://www.ruby-forum.com/.