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A144981
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Decimal expansion of cos(Pi/8) = cos(22.5 degrees).
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4
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9, 2, 3, 8, 7, 9, 5, 3, 2, 5, 1, 1, 2, 8, 6, 7, 5, 6, 1, 2, 8, 1, 8, 3, 1, 8, 9, 3, 9, 6, 7, 8, 8, 2, 8, 6, 8, 2, 2, 4, 1, 6, 6, 2, 5, 8, 6, 3, 6, 4, 2, 4, 8, 6, 1, 1, 5, 0, 9, 7, 7, 3, 1, 2, 8, 0, 5, 3, 5, 0, 0, 7, 5, 0, 1, 1, 0, 2, 3, 5, 8, 7, 1, 4, 8, 3, 9, 9, 3, 4, 8, 5, 0, 3, 4, 4, 5, 9, 6, 0, 9, 7, 9, 6, 3
(list; constant; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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COMMENTS
| cos(Pi/5) is A019863. cos(Pi/6) is A010527. cos(Pi/7) is A073052. cos(Pi/9) is A019879.
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LINKS
| Anonymous, Exact trigonometric constants, Wikipedia
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FORMULA
| (2+2^(1/2))^(1/2)/2 = sqrt(3.41421....)/2 = 1.8477759.../2 .
Equals 2F1(11/16,5/16;1/2;3/4) / 2. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 27 2008]
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EXAMPLE
| Equals 0.923879532511286756128183189396788286822416625863642486115097...
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MAPLE
| evalf(sqrt(2+sqrt(2))/2) ;
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MATHEMATICA
| RealDigits[ Sqrt[2 + Sqrt[2]]/2, 10, 111][[1]] (* 0r *) RealDigits[ Cos[Pi/8], 10, 111][[1]] (* RGWv *)
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CROSSREFS
| Cf. A195909, A195913, A195697. - Mohammad K. Azarian, Oct 11 2011
Sequence in context: A160108 A011344 A137197 * A200282 A133841 A099769
Adjacent sequences: A144978 A144979 A144980 * A144982 A144983 A144984
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KEYWORD
| cons,easy,nonn
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AUTHOR
| R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Sep 28 2008
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