Решебник по алгебре 9 класс Макарычев Задание 639

 

\[\boxed{\text{639\ (639).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]

\[x_{1} = 2,0 \cdot 10^{4}\ м^{3};\ \ q = 1,1\ (так\ как\ прирост\ 10\%).\]

\[x_{7} = 2 \cdot 10^{4} \cdot (1 + 0,1)^{6} \approx 35\ 431\ м^{3}.\]

\[Ответ:через\ 6\ лет\ количество\ древесины\ на\ этом\ участке\ будет\]

\[равно\ 35\ 431\ м^{3}.\]

\[\boxed{\text{639.}\text{\ }\text{ОК\ ГДЗ\ -\ домашка\ на\ 5}}\]

\[\textbf{а)}\ y_{1} = - 3;\ \ \ \ \ \ y_{n + 1} = 10 + y_{n}\ \]

\[y_{2} = - 3 + 10 = 7,\ \ \]

\[y_{3} = 7 + 10 = 17,\]

\[y_{4} = 17 + 10 = 27,\ \ \]

\[y_{5} = 27 + 10 = 37.\]

\[\textbf{б)}\ y_{1} = 10;\ \ \ y_{n + 1} = \frac{2,5}{y_{n}}\]

\[y_{2} = 2,5\ :10 = 0,25,\]

\[y_{3} = 2,5\ :0,25 = 10,\]

\[y_{4} = 2,5\ :10 = 0,25,\]

\[y_{5} = 2,5\ :0,25 = 10.\]

\[\textbf{в)}\ y_{1} = 1,5;\ \ \ \ y_{n + 1} = n + y_{n}\]

\[y_{2} = 1,5 + 1 = 2,5;\]

\[y_{3} = 2,5 + 2 = 4,5\]

\[y_{4} = 4,5 + 3 = 7,5;\]

\[y_{5} = 7,5 + 4 = 11,5.\]

\[\textbf{г)}\ y_{1} = - 4;\ \ \ \ y_{n + 1} = - n^{2} \cdot y_{n}\]

\[y_{2} = - 1^{2} \cdot ( - 4) = 4,\]

\[y_{3} = - 2^{2} \cdot 4 = - 16,\]

\[y_{4} = - 3^{2} \cdot ( - 16) = 144,\]

\[y_{5} = - 4^{2} \cdot 144 = - 2304.\]