Відповіді на вправи: 600

1) a₁ = 5; d = 8.

a₂ = 5 + 8 = 13;

a₃ = 13 + 8 = 21;

a₄ = 21 + 8 = 29;

a₅ = 29 + 8 = 37;

(a_n): 5; 13; 21; 29; 37,…

2) a₁ = 10; d = –7.

a₂ = 10 – 7 = 3;

a₃ = 3 – 7 = –4;

a₄ = –4 – 7 = –11;

a₅ = –11 – 7 = –18;

(a_n): 10; 3; –4; –11; –18;…

3) a₁ = 0,2; d = 5.

a₂ = 0,2 + 5 = 5,2;

a₃ = 5,2 + 5 = 10,2;

a₄ = 10,2 + 5 = 15,2;

a₅ = 15,2 + 5 = 20,2;

(a_n): 0,2; 5,2; 10,2; 15,2; 20,2,…

4) a₁ = 4,5; d = –2.

a₂ = 4,5 – 2 = 2,5;

a₃ = 2,5 – 2 = 0,5;

a₄ = 0,5 – 2 = –1,5;

a₅ = –1,5 – 2 = –3,5;

(a_n): 4,5; 2,5; 0,5; –1,5; –3,5

5) a₁ = –1,5; d = –0,4.

a₂ = –1,5 – 0,4 = –1,9;

a₃ = –1,9 – 0,4 = –2,3;

a₄ = –2,3 – 0,4 = –2,7;

a₅ = –2,7 – 0,4 = –3,1;

(a_n): –1,5; –1,9; –2,3; –2,7; –3,1.

6) a₁ = $\frac{5}{7}$; d = –$\frac{3}{14}$.

a₂ = $\frac{5}{7}$ – $\frac{3}{14}$ = $\frac{10}{14}$ – $\frac{3}{14}$ = $\frac{1}{2}$;

a₃ = $\frac{1}{2}$ – $\frac{3}{14}$ = $\frac{7}{14}$ – $\frac{3}{14}$ = $\frac{2}{7}$;

a₄ = $\frac{2}{7}$ – $\frac{3}{14}$ = $\frac{4}{14}$ – $\frac{3}{14}$ = $\frac{1}{14}$;

a₅ = $\frac{1}{14}$ – $\frac{3}{14}$ = –$\frac{2}{14}$ = –$\frac{1}{7}$;

(a_n): $\frac{5}{7}$; $\frac{1}{2}$; $\frac{2}{7}$; $\frac{1}{14}$; –$\frac{1}{7}$.