182. Найдите четыре первых члена последовательности (а), если: 1) a₁ = 2, an+1 = an-3; 2) a₁ = 27, an+1=81; an 3) a₁ = 0,1, a₂ = -0,1, an+ 2 = 3an + an+1; 4) a₁ = a₂ = 1, An + 2 = An + an+1

1) a₁ = 2, aₙ₊₁ = aₙ - 3:

• a₁ = 2
• a₂ = a₁ - 3 = 2 - 3 = -1
• a₃ = a₂ - 3 = -1 - 3 = -4
• a₄ = a₃ - 3 = -4 - 3 = -7

2) a₁ = 27, aₙ₊₁ = \(\frac{81}{a_n}\):

• a₁ = 27
• a₂ = \(\frac{81}{a_1}\) = \(\frac{81}{27}\) = 3
• a₃ = \(\frac{81}{a_2}\) = \(\frac{81}{3}\) = 27
• a₄ = \(\frac{81}{a_3}\) = \(\frac{81}{27}\) = 3

3) a₁ = 0.1, a₂ = -0.1, aₙ₊₂ = 3aₙ + aₙ₊₁:

• a₁ = 0.1
• a₂ = -0.1
• a₃ = 3a₁ + a₂ = 3(0.1) + (-0.1) = 0.3 - 0.1 = 0.2
• a₄ = 3a₂ + a₃ = 3(-0.1) + 0.2 = -0.3 + 0.2 = -0.1

4) a₁ = a₂ = 1, aₙ₊₂ = aₙ + aₙ₊₁:

• a₁ = 1
• a₂ = 1
• a₃ = a₁ + a₂ = 1 + 1 = 2
• a₄ = a₂ + a₃ = 1 + 2 = 3

Ответ: 1) 2, -1, -4, -7; 2) 27, 3, 27, 3; 3) 0.1, -0.1, 0.2, -0.1; 4) 1, 1, 2, 3