Відповіді на вправи: 601

1) a₁ = 12; d = 8.

a₂ = 12 + 8 = 20;

a₃ = 20 + 8 = 28;

a₄ = 28 + 8 = 36;

a₅ = 37 + 8 = 44;

(a_n): 12; 20; 28; 36; 44,…

2) a₁ = –5; d = 15.

a₂ = –5 + 15 = 10;

a₃ = 10 + 15 = 25;

a₄ = 25 + 15 = 40;

a₅ = 40 + 15 = 55;

(a_n): –5; 10; 25; 40; 55;…

3) a₁ = 7,5; d = –2,5.

a₂ = 7,5 – 2,5 = 5;

a₃ = 5 – 2,5 = 2,5;

a₄ = 2,5 – 2,5 = 0;

a₅ = 0 – 2,5 = –2,5;

(a_n): 7,5; 5; 2,5; 0; –2,5,…

4) a₁ = $\frac{5}{6}$; d = $\frac{1}{12}$.

a₂ = $\frac{5}{6}$ + $\frac{1}{12}$ = $\frac{10}{12}$ + $\frac{1}{12}$ = $\frac{11}{12}$;

a₃ = $\frac{11}{12}$ + $\frac{1}{12}$ = $\frac{12}{12}$ = 1;

a₄ = 1 + $\frac{1}{12}$ = 1$\frac{1}{12}$;

a₅ = 1$\frac{1}{12}$ + $\frac{1}{12}$ = 1$\frac{2}{12}$ = 1$\frac{1}{6}$;

(a_n): $\frac{5}{6}$; $\frac{11}{12}$; 1; 1$\frac{1}{12}$; 1$\frac{1}{6}$,…