(х+2)^2/2-х^2-4/4-(х-2)^2/8=х^2/8
Упрощаем:
(х^2+4х+4)/2 - (х^2-4)/4 - (х^2-4х+4)/8 - х^2/8=0 |×8
4х^2+16х+16-2х^2+8-х^2+4х-4-x^2=0
20х+20=0
20х=-20
х= - 1
Отв: -1
{2z + 5y = 63
{ z + 7y = 10 | * (-2)
{ 2z + 5y = 63
{ -2z -14y = - 20
(2z + 5y ) + ( - 2z - 14y) = 63 + ( - 20)
- 9y = 43
y = 43 : ( - 9) = - ⁴³/₉
у = - 4 ⁷/₉
z + 7 * (- 4 ⁷/₉) = 10
z + ⁷/₁ * ( - ⁴³/₉) = 10
z - ³⁰¹/₉ = 10
z - 33 ⁴/₉ = 10
z = 10 + 33 ⁴/₉
z = 43 ⁴/₉
Ответ : z = 43 ⁴/₉ ; у = - 4 ⁷/₉ .
<span>COS(A+П/4)*COS(A-П/4) = (1/2)* [cos(</span>α + π/4 - α + π/4) + cos(α + π/4 + α - π/4)] =
= (1/2)* [ cos(π/2) + cos2α] = (1/2)*cos(2α)
<span>sin x -cos x =n</span>