Sсектора=П*R^2/360 *a
=> П*64/360 *80=128П/9
<span>( (sin^2(</span>π<span>+ </span>α<span>)+sin^2(</span>π<span>/2 + </span>α<span>))= Sin</span>²α + Cos²α = 1<span>
cos(3</span>π<span>/2 + </span>α<span>) ) * сtg(3</span>π<span>/2 - </span>α<span>)= Sin</span>α * tgα= Sin²α/Сosα
Ответ: Cosα/Sin²α
Ответ:
1) -3x + 2 = -8x + 7 + 5x
-3х + 8х - 5х = 7 - 2
0х = 5
Ответ: ∅
2) 5 - 3(x + 7) = 8x - 6x - 8
5 - 3x - 21 = 2x - 8
-3x - 2x = -8 - 5 +21
-5x = 8
x = -1,6
3) (9x - 2)(3x + 27) = 0
27x² + 243x - 6x - 54 = 0
27x² + 237x - 54 = 0
D = 56169 + 5832 = 62001
4) 5 - (6x - 2) = 7x + (-3x + 1)
5 - 6x + 2 - 7x + 3x - 1 = 0
-10x + 6 = 0
-10x = -6
x = 0,6
5) x(x + 25)=0
x₁ = 0
x₂ = -25