Proszę potrzebne na jutro plisss !!!! Proszę bez głupich linków, odpowiedzi i komentarzy itp.

ćwiczenie 7 a) a₁ = 7 a₂ = 11 a₂ - a₁ = r r = 11 - 7 = 4 an = 51 an = a₁ + (n - 1) * r 51 = 7 + (n - 1) * 4 51 = 7 + 4n - 4 51 - 7 + 4 = 4n 4n = 48 n = 48 : 4 = 12 a₁ = 7 a₁₂ = 51 S₁₂ = (a₁ + a₁₂)* 12/2 = (7 + 51) * 6 = 58 * 6 = 348 odp S₁₂ = 348 b) a₁ = 1/2 a₂ = 1 a₂ - a₁ = r r = 1 - 1/2 = 1/2 an = a₁ + (n -1) * r = 100 100 = 1/2 + (n - 1) * 1/2 100 = 1/2 + 1/2n - 1/2 1/2n = 100 n = 100 * 2 = 200 a₂₀₀ = 100 S₂₀₀ = (a₁ + an) * n/2 = (1/2 + 100) * 200/2 = 100 1/2 * 100 = 100,5 * 100 = = 10050