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A137617 Decimal expansion of volume of the solid of revolution generated by a Reuleaux triangle rotated around one of its symmetry axes. +0
4
4, 4, 9, 4, 6, 1, 0, 3, 5, 5, 4, 4, 9, 6, 9, 0, 5, 5, 8, 3, 6, 0, 1, 3, 7, 5, 5, 5, 4, 0, 3, 1, 0, 0, 6, 6, 9, 1, 2, 4, 9, 6, 3, 6, 5, 0, 4, 3, 2, 7, 2, 1, 0, 9, 5, 8, 1, 0, 7, 1, 4, 9, 8, 8, 3, 5, 2, 0, 3, 4, 6, 7, 1, 2, 0, 9, 3, 8, 4, 5, 8, 5, 8, 5, 0, 6, 0, 9, 8, 2, 9, 4, 1, 6, 5, 2, 6, 7, 3, 3, 5 (list; cons; graph; listen)
OFFSET

0,1

COMMENT

The rotated Reuleaux triangle is not only a body of constant width, it is the minimum volume surface of revolution width constant width (Campi et al. 1996).

REFERENCES

St. Campi, A. Colesanti and P. Gronchi, Minimum problems for volumes of convex bodies, Partial Differential Equations and Applications - Collected Papers in Honor of Carlo Pucci, Marcel Dekker (1996), pp. 43-55.

LINKS

SwissEduc - Teaching and Learning Mathematics, Gleichdick - Koerper konstanter Breite (in German and English)

FORMULA

2/3 * Pi - Pi^2 / 6

EXAMPLE

0.44946103...

MATHEMATICA

k1[x_] := Sqrt[1 - (x - Sqrt[3]/2)^2]; k2[x_] := Sqrt[1 - x^2] - 1/2; Pi * Integrate[k1[x]^2, {x, Sqrt[3]/2 - 1, 0}] + Pi * Integrate[k2[x]^2, {x, 0, Sqrt[3]/2}]

CROSSREFS

Cf. A102888, A137615, A137616, A137618.

Sequence in context: A068340 A097667 A019627 this_sequence A023405 A160900 A035116

Adjacent sequences: A137614 A137615 A137616 this_sequence A137618 A137619 A137620

KEYWORD

cons,easy,nonn

AUTHOR

Christof Weber (christof.weber(AT)igb.uzh.ch), Feb 04 2008

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Last modified December 10 12:37 EST 2009. Contains 170569 sequences.


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