015.14. a) x = n² + 1; n б) у = -п³ - 10; n B) z = -n³ + 5; n г) w = n² - 15.

15.14.

1. a) $$ x_n = n^2 + 1 $$




• n = 1; $$ x_1 = 1^2 + 1 = 2 $$


• n = 2; $$ x_2 = 2^2 + 1 = 5 $$


• n = 3; $$ x_3 = 3^2 + 1 = 10 $$


• n = 4; $$ x_4 = 4^2 + 1 = 17 $$


• n = 5; $$ x_5 = 5^2 + 1 = 26 $$



Ответ: 2; 5; 10; 17; 26.

2. б) $$ y_n = -n^3 - 10 $$




• n = 1; $$ y_1 = -1^3 - 10 = -11 $$


• n = 2; $$ y_2 = -2^3 - 10 = -18 $$


• n = 3; $$ y_3 = -3^3 - 10 = -37 $$


• n = 4; $$ y_4 = -4^3 - 10 = -74 $$


• n = 5; $$ y_5 = -5^3 - 10 = -135 $$



Ответ: -11; -18; -37; -74; -135.

3. B) $$ z_n = -n^3 + 5 $$




• n = 1; $$ z_1 = -1^3 + 5 = 4 $$


• n = 2; $$ z_2 = -2^3 + 5 = -3 $$


• n = 3; $$ z_3 = -3^3 + 5 = -22 $$


• n = 4; $$ z_4 = -4^3 + 5 = -59 $$


• n = 5; $$ z_5 = -5^3 + 5 = -120 $$



Ответ: 4; -3; -22; -59; -120.

4. г) $$ w_n = n^2 - 15 $$




• n = 1; $$ w_1 = 1^2 - 15 = -14 $$


• n = 2; $$ w_2 = 2^2 - 15 = -11 $$


• n = 3; $$ w_3 = 3^2 - 15 = -6 $$


• n = 4; $$ w_4 = 4^2 - 15 = 1 $$


• n = 5; $$ w_5 = 5^2 - 15 = 10 $$



Ответ: -14; -11; -6; 1; 10.