Odpowiedź:
zad 1
a₆ = a₁ + 5r
a₈ = a₁ + 7r
a₁+5r + a₁+7r = 4
2a₁ + 12r = 4 | ; 2
a₁ + 6r = 2
a₁ + 6r = a₇ = 2
zad 2
an = 1/3 * n + 2
a₁ = 1/3 * 1 + 2 = 1/3 + 2 = 2 1/3
a₂ = 1/3 * 2 + 2 = 2/3 + 2 = 2 2/3
r = a₂ - a₁ = 2 2/3 - 2 1/3 = 1/3
zad 3
a₁ = 36
a₂ = 6x
a₃ = 25
a₂² = a₁ * a₃ = 36 * 25 = 900
a₂ = √900 = 30
zad 4
a₁ = - 3
a₄= a₁q³ = 192
a₄/a₁ = a₁q³/a₁ = q³
q³ = 192
q = ∛192 = ∛(64 * 3)= 4∛3
