Решение
1 + cos(x + π/2) + cos(x - π/2) =
= 1 - sinx - sinx = 1 - 2sinx
при x = 5π/12
1 - 2sinx = 1 - 2sin(5π/12) = 1 - 2sin75° = 1 - 2 * 0,9659 = 1 - 1,9318 = - 0,9318
1)
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2)
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3)
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4)
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5)
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6)
2х² +7х + 3 = 0
D=7²-2*3*4=25=5²
х₁=(-7+5)/4=-0,5
х₂=(-7-5)/4=-3
<span>Tg(2°) × ctg(2°) + sin(2°) =РЕШЕНИЕ НА ФОТКЕ</span>