0,125 * 4 в степени 2х-3 = (1/4корень2) в степени-х

0,125 * 4^(2х-3) = (1/4корня из2)^(-х) 1/8 * (2^2)^(2х-3) = (1/(2^2) * 2^(1/2))^(-х) 2^(-3) * 2^(4х - 6) = (1/(2^2цел 1/2))^(-х) 2^(4х - 9) = (2^(-2,5))^(-х) 2^(4х - 9) = 2^2,5х 4х - 9 = 2,5х 1,5х = 9 х = 6

= sin3b/cos3b - sinb/cosb = (sin3bcosb - cos3bsinb)/cos3bcosb = sin(3b-b)/

/( (cos3b+cosb)/2 ) = 2sin2b/cos4b

возможно такое преобразование

1.

1) b₁ = 2*5¹ = 2*5 = 10,   b₂ = 2*5² = 2*25 = 50,   bn = 2*5^n

2) q = b₂ / b₁ = 50 / 10 = 5

3) sn = (b₁ - bn*q)/(1-q) = (10 - 2*5^n * 5) / (1-5) = (10 - 10*5^n)/(-4) = 10 (1 - 5^n) / (-4) = 2,5(1-5^n)

 

2.

1) q = c₂/c₁ = -5 / (-5/9)   = 9

2) c₈ = c₁ * q^(n-1) = (-5/9) * 9^(8-1) = (-5/9) * 9^7 = -5 * 9^6 = - 2657205