po moemu tut chego to nehvataet, napiwi ewe raz vopros...
Arccos (0) + arcsin (-1/2) - 2•arcsin (-1) + 12•arccos (-sqrt3/2) = π/2 + (-π/6) - 2•(-π/2) + 12•5π/6 = π/2 - π/6 + π + 10π = π/3 + 11π = 34π/3
(2х-у)^2-х^2 = 4х^2 - у^2 - х^2 = 3х^2- у^2
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