a ArcCos[x] + b ArcCos[y] == (Pi (a + b))/2 - 2 I Pi (Floor[(-Arg[(I x + Sqrt[1 - x^2])^(I a)] - Arg[(I y + Sqrt[1 - y^2])^(I b)] + Pi)/(2 Pi)] + Floor[(Pi - Re[a Log[I x + Sqrt[1 - x^2]]])/(2 Pi)] + Floor[(Pi - Re[b Log[I y + Sqrt[1 - y^2]]])/(2 Pi)]) + Log[(I x + Sqrt[1 - x^2])^(I a) (I y + Sqrt[1 - y^2])^(I b)]

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2007-05-02