From: Brian Candler <b.candler@...>
Date: 2008-12-20T20:29:13+09:00
Subject: Re: about Float

I get the correct answer using bc too:

$ bc
scale=100
x=77617
y=33096
t1=(333.75-x*x)*y*y*y*y*y*y
t2=x*x*(11*x*x*y*y - 121*y*y*y*y - 2)
t3=5.5*y*y*y*y*y*y*y*y
t4=x/(2*y)
t1+t2+t3+t4
-.827396059946821368141165095479816291999033115784384819917814841672\
7096930142615421803239062122310854

However, using BigDecimal, the answer is remarkably different:

  require "bigdecimal"
  puts f(BigDecimal.new("77167.0"),BigDecimal.new("33096.0"))
  # => 9.15359360631475e+34

That's a sign plus 35 orders of magnitude different :-)
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