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The number of UNIX installations has grown to 10, with more expected.

--The Unix Programmer's Manual, 2nd Edition, June 1972

--The Unix Programmer's Manual, 2nd Edition, June 1972

$$\cos x = \sum\limits_{n = 0}^\infty {\frac{{\left( { - 1} \right)^n x^{2n} }}{{\left( {2n} \right)!}}}$$