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Old 2006-06-05, 20:25   #2
R. Gerbicz
 
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"Robert Gerbicz"
Oct 2005
Hungary

22·349 Posts
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Quote:
Originally Posted by R.D. Silverman
It was tedious to do by hand. i.e. please verify that f(2z + 1/z) equals
the 12th degree polynomial divided by z^6.
Using Pari-Gp I've gotten:

(22:20) gp > f(x)=x^6+2*x^5-10*x^4-20*x^3+16*x^2-48*x+72
(22:20) gp > substpol(f(x),x,2*z+1/z)
%7 = (64*z^12 + 64*z^11 + 32*z^10 - 16*z^8 - 176*z^7 + 56*z^6 - 8*z^5 - 4*z^4 + 2*z^2 + 2*z + 1)/z^6
(22:20) gp >

So there are errors in your polynom.

Last fiddled with by R. Gerbicz on 2006-06-05 at 20:27
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