Свойства арифметической прогресси

Question

Свойства арифметической прогресси

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Answer 1

Хn = 5· 3n²
n = 1  x1 = 5 · 3 · 1² = 15
n = 2  x2 = 5 · 3 · 2² = 60
n = 3  x3 = 5 · 3 · 3² = 135
n = 4  x4 = 5 · 3 · 4² = 240
n = 5  x5 = 5 · 3 · 5² = 375

bn = 3 + 5(n - 1)
b1 = 3
b2 = 3 + 5 = 8
b3 = 8  + 5 = 13
b4 = 13 + 5 = 18
b5 = 18 + 5 = 23