<span>(6а-7)^2-(4а-2)^2=(6a-7+4a-2)(6a-7-4a+2)=(10a-9)(2a-5)</span>
Arcsin1/2-3arcsin(-1/2)-2arccos(-1) = π/6 - 3*(-π/6) - 2π = π/6 + π/2 - 2π = -4π/3
6.а7.г...........................................................
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[-6]------------[-2]------------------(4)---------------------(6)-
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[-6;4)∩[-2;6)=[-2;4)
(-2+4)/2=1
Окрестность 1
Радиус равен |4-(-2)|/2=6/2=3