Sin⁴xCos²x - Cos⁴xSin²x = Cos2x
Sin²xCos²x(Sin²x - Cos²x) - Cos2x = 0
Sin²xCos²x * (- Cos2x) - Cos2x = 0
Cos2x(Sin²xCos²x + 1) = 0
Cos2x = 0 Sin²xCos²x + 1 = 0
2x = π/2 + πn , n ∈ z 1/4Sin²2x + 1 = 0
x = π/4 + πn/2 , n ∈ z Sin²2x = - 4 - решений нет
Ответ : π/4 + πn/2 , n ∈ z
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1)
5х+6=12.5х
12.5х-5х=6
7.5х=6
х=6÷7.5
х=0.8
2)
12-8х+24=6+4х
36-8х=6+4х
4х+8х=36-6
12х=30
х=30÷12
х=2.5
5,4*0,8=4,32
4,32+0,08=4,4