cos2x+sin²x = 0,75
cos²x - sin²x + sin²x = 0.75
cos²x = 0.75
cosx = ±√0.75 = ±0.5√3
1) cosx = -0.5√3
x₁ = 5π/6 + 2πn
x₂ = -5π/6 + 2πn
n =1 x₁ = (2 + 5/6) π x∉[π; 5π/2]
x₂ = (2- 5/6) π = 7π/6 x∈[π; 5π/2]
n =2 x₁ = (4 + 5/6) π x∉[π; 5π/2]
x₂ = (4- 5/6) π x∉[π; 5π/2]
2) cosx = 0.5√3
x₁ = π/6 + 2πn
x₂ = -π/6 + 2πn
n =1 x₁ = (2 + 1/6) π = 13π/6 x∈[π; 5π/2]
x₂ = (2 - 1/6) π = 11π/6 x∈[π; 5π/2]
n =2 x₁ = (4 + 1/6) π x∉[π; 5π/2]
x₂ = (4- 1/6) π x∉[π; 5π/2]
Ответ: x = 7π/6; 11π/6; 13π/6
(a+2/3)+1/3 = a+(2/3+1/3) = а + 3/3 = а + 1
1 кг=1000 г
1) 500 г - 286 руб.
1000 г - х руб.
х=1000*286/500=572 руб. - за 1 кг
2) 250 г - 112 руб.
1000 г -х руб.
х=1000*112/250=448 руб. - за 1 кг
3) 300 г - 180 руб.
1000 г - х руб.
х=1000*180/300=600 руб. - за 1 кг
4) 500 г - 300 руб.
1000 г - х руб.
х=1000*300/500=600 руб. - за 1 кг
Ответ: наименьшая цена за 1 кг сосисок 448 руб.