Решение
a) уn = 2n² - n
y₁ = 2*1² - 1 = 1
y₂ = 2*2² - 2 = 6
y₃ = 2*3² - 3 = 18 - 3 = 15
y₄ = 2*4² - 4 = 32 - 4 = 28
y₅ = 2*5² - 5 = 50 - 5 = 45
б) yn = (-1)^n / (n^2+1)
y₁ = (-1)¹ / (1² + 1) = - 1/2
y₂ = (-1)² / (2² + 1) = 1/5
y₃ = (-1)³ / (3² + 1) = - 1/10
y₄ = (-1)⁴ / (4² + 1) = 1/17
y₅ = (-1)⁵ / (5² + 1) = - 1/26