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Accuracy and Precision

• To: mathgroup at smc.vnet.net
• Subject: [mg36853] Accuracy and Precision
• From: pkosta2002 at yahoo.com (Peter Kosta)
• Date: Sun, 29 Sep 2002 02:55:19 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

Could someone explain what is going on here, please?

In[1]:= 
a = 77617.; b = 33096.; 

In[2]:=
SetAccuracy[a, Infinity]; SetAccuracy[b, Infinity]; 
SetPrecision[a, Infinity]; SetPrecision[b, Infinity]; 

In[4]:=
f := 333.75*b^6 + a^2*(11*a^2*b^2 - b^6 - 121*b^4 - 2) + 5.5*b^8 + a/(2*b)

In[5]:=
SetAccuracy[f, Infinity]; SetPrecision[f, Infinity]; 

In[6]:=
f

Out[6]=
-1.1805916207174113*^21

In[7]:=
a = 77617; b = 33096; 

In[8]:=
g := (33375/100)*b^6 + a^2*(11*a^2*b^2 - b^6 - 121*b^4 - 2) + (55/10)*b^8 + a/(2*b)

In[9]:=
g

Out[9]=
-(54767/66192)

In[10]:=
N[%]

Out[10]=
-0.8273960599468214

Thanks,

PK