8Sin²(π/8 -2x) - Cos²(π/8 -2x) = 1/2Sin(4x -π/4)
8Sin²(π/8 -2x) - (1 - Sin²(π/8 -2x)) = 1/2Sin(4x -π/4)
Sin²(π/8 -2x) +7Sin²(π/8 -2x) - (1 - Sin²(π/8 -2x)) = 1/2Sin(4x -π/4)
Sin²(π/8 -2x) +7Sin²(π/8 -2x) - 1 + Sin²(π/8 -2x) = 1/2Sin(4x -π/4)
7Sin²(π/8 -2x) = 1/2*2Sin(2x -π/8)Cos(2x -π/8)
7Sin²(π/8 -2x) = Sin(2x -π/8)Cos(2x -π/8)
7Sin²(π/8 -2x) - Sin(2x -π/8)Cos(2x -π/8) = 0
7Sin²(π/8 -2x) + Sin(π/8 -2x)Cos(2x -π/8) =0
Sin(π/8 -2x)(7Sin(π/8 -2x + Cos(π/8 -2x)) = 0
Sin(π/8 -2x) = 0 или 7Sin(π/8 -2x + Cos(π/8 -2x)= 0 | : Cos(π/8 -2x)≠0
π/8 -2x = πn, n∈Z 7tg(π/8 -2x) +1 = 0
2x = π/8 - πn , n∈Z tg(π/8 -2x) = -1/7
x = π/16 -πn/2, n ∈Z π/8 -2x = arctg(-1/7) + πk , k ∈ Z
x = π/16 +2arctg(1/7) -2πk , k ∈Z
An=-12;-6;...
a1=-12
d=an+1-an= -6-12=-18
a17= a1+d(17-1)
a17= -12-18*18= -12-324=-336
Ответ:
Объяснение:
(3x-5)^5=(3x)^5-5(3x)^4a+10(3x)³a²-10(3x)²a³+5*3x*a^4-a^5=
=243x^5-405x^4a+270x³a²-90x²a³+15xa^4-a^5
1) (a+3)^2 + (a-3)(a+3) + 6a = a^2 + 6a + 9 + a^2 - 3^2 +6a = 2a^2 + 12a
2) xy-2y=y(x-2)
16a^2 - 81 = 4^2a^2 - 9^2 = (4a-9)(4a+9)
3x^2 - 6x^3 = 3x^2(1-2x)
x^2-10x+25 = (x-5)^2
3(x-1) +y(x-1) = (x-1)(3+y)
2a^2 - 4ab + 2b^2 = 2(a-b)^2
3) a^2 - 3ab + 3a - 9b = a(a+3) - 3b(a+3) = (a+3)(a-3b) = (1 + 3)*[1-3*(-1/3)]=
= 4*[1 + 1] =8