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A305327
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Decimal expansion of the middle x such that 1/x + 1/(x+1) + 1/(x+2) = 1.
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3
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5, 3, 9, 1, 8, 8, 8, 7, 2, 8, 1, 0, 8, 8, 9, 1, 1, 6, 5, 2, 5, 8, 7, 5, 9, 0, 2, 6, 9, 8, 5, 2, 0, 0, 0, 8, 0, 9, 9, 8, 8, 7, 1, 0, 9, 5, 4, 2, 1, 2, 6, 7, 0, 1, 7, 1, 9, 2, 2, 8, 4, 4, 6, 6, 6, 7, 6, 8, 6, 0, 0, 3, 4, 4, 2, 7, 6, 6, 9, 5, 5, 0, 5, 3, 7, 6
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OFFSET
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0,1
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COMMENTS
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Equivalently, the middle root of x^3 - 4*x - 2;
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LINKS
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FORMULA
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greatest: (4*cos((1/3)*arctan(sqrt(37/3)/3)))/sqrt(3);
middle: -((2*cos((1/3)*arctan(sqrt(37/3)/3)))/sqrt(3)) + 2*sin((1/3)*arctan(sqrt(37/3)/3));
least: -((2*cos((1/3)*arctan(sqrt(37/3)/3)))/sqrt(3)) - 2*sin((1/3)*arctan(sqrt(37/3)/3)).
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EXAMPLE
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greatest root: 2.214319743377535187...
middle root: -0.539188872810889116...
least root: -1.67513087056664607088...
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MATHEMATICA
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r[x_] := 1/x + 1/(x + 1) + 1/(x + 2);
-Numerator[Factor[r[x] - 1]]
t = x /. ComplexExpand[Solve[r[x] == 1, x]]
u = N[t, 120]
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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