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Re: Answer for Simplify[Cos[x]^4Sin[x]^4]?
 To: mathgroup at smc.vnet.net
 Subject: [mg104450] Re: Answer for Simplify[Cos[x]^4Sin[x]^4]?
 From: Bill Rowe <readnews at sbcglobal.net>
 Date: Sun, 1 Nov 2009 03:57:38 0500 (EST)
On 10/30/09 at 2:19 AM, lawrenceteo at yahoo.com (Lawrence Teo) wrote:
>We know that Simplify[Cos[x]^2Sin[x]^2] > Cos[2 x] But why
>Simplify[Cos[x]^4Sin[x]^4] > Cos[2 x] too?
>Doing subtraction between the two expressions will give small delta.
>This is enough to prove that the two expression shouldn't be the
>same.
When you did the subtraction did you do:
In[5]:= Cos[x]^2  Sin[x]^2  (Cos[x]^4  Sin[x]^4) // Simplify
Out[5]= 0
which is correct. Or did you fail to include the parentheses and do
In[6]:= Cos[x]^2  Sin[x]^2  Cos[x]^4  Sin[x]^4 // Simplify
Out[6]= 2 sin^4(x)
Since, this result could be characterized as a "small delta", my
guess is this is what you did. But this is not the difference
between the two expressions.
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