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A118178 Decimal expansion of arc length of eight curve. +0
1
6, 0, 9, 7, 2, 2, 3, 4, 7, 0, 1, 0, 4, 9, 1, 6, 0, 4, 6, 4, 3, 0, 3, 7, 4, 2, 0, 5, 6, 7, 3, 9, 9, 7, 8, 3, 3, 4, 9, 2, 3, 3, 7, 8, 1, 8, 3, 8, 6, 5, 5, 5, 1, 1, 4, 8, 6, 6, 1, 7, 3, 2, 1, 0, 0, 8, 2, 0, 4, 3, 7, 5, 4, 9, 4, 4, 1, 4, 0, 9, 3, 2, 0, 1, 3, 5, 4, 9, 6, 1, 4, 3, 3, 6, 5, 9, 1, 7, 6, 1, 0, 7, 7, 7, 0 (list; cons; graph; listen)
OFFSET

1,1

LINKS

Eric Weisstein's World of Mathematics, Eight Curve

FORMULA

4*Integrate[Sqrt[4*Sin[t]^4-5*Sin[t]^2+2], {t, 0, Pi/2}].

Can be expressed in terms of complete elliptic integrals. Using Mathematica notation, with m = (4 + Sqrt[2])/8, the arc length is 4*2^(1/4)*(EllipticE[m] - EllipticK[m]) + (3 + 2*Sqrt[2])*2^(-1/4)*EllipticPi[(4 - 3*Sqrt[2])/8, m]. - David W. Cantrell, Apr 22 2006

EXAMPLE

6.097223470104916046...

MATHEMATICA

RealDigits[4*NIntegrate[Sqrt[4*Sin[t]^4-5*Sin[t]^2+2], {t, 0, Pi/2}, WorkingPrecision->200], 10, 110][[1]]

CROSSREFS

Sequence in context: A016628 A112246 A153201 this_sequence A021168 A147709 A153314

Adjacent sequences: A118175 A118176 A118177 this_sequence A118179 A118180 A118181

KEYWORD

nonn,cons

AUTHOR

Eric Weisstein (eric(AT)weisstein.com), Apr 13, 2006

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Last modified November 24 23:16 EST 2009. Contains 167481 sequences.


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