Y=√((x²-4)x)
(x²-4)x≥0
a)(x²-4)≥ 0 ∧ x≥0
x²≥4 ∧ x≥0
x≥2
x∈/2,∞)
b)(x²-4)≤0 ∧ x≤0
x²≤4 ∧ x≤0
x∈/-2,2/ ∧ x≤0
x∈/-2,0/
Otvet: x∈/-2,0/ ∪ x∈/2,∞)
А) cos β + cos((2π/3)+β) + <span>cos((2π/3)-β) =
</span>cos β + cos(2π/3)*cos β + sin(2π/3)*sin β + cos(2π/3)*cos β - sin(2π/3)*sin <span>β =
= </span>cos β + (-1/2)*cos β + (√2/3)*sin β + (-1/2)*cos β - (√2/3)*sin <span>β = = 0.
б) ((2tg</span>α) / (1+tg²α))*2cos(2α) = tg(2α)*2cos(2α) =
= sin(2α)*2cos(2α) / cos(2α) = 2 sin(2α).
Тут очень просто же
кароче 57675787