25 метров будет постоянно
Решение
Упростить:
cos40° cos20° = 1/2[cos(40° - 20°) + cos(40° + 20°) ] =
= 1/2[cos20° + cos60°] = (1/2)*cos20° + 1/4
X=317
a=427
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Пошаговое объяснение:
Я так понимаю вам нужно на 5, так что вот:
1)
9x²-6x+1>0
(3x-1)²>0
x∈R (т.к. (3x-1)² всегда больше нуля)
2)
3x²-x+2≤0
D=1-4*6=1-24=-23<0 => ø (Или по простому решения нет)
3) 7≥x²
-√7≤x≤√7
Решение задания смотри на фотографии