Question

Помогите срочно, даю 20 баллов

Answer 1

Ответ:

2)

$a _{1} = - 1 \\ a _{n + 1} = a_{n} - 0.3$

$a_{1 + 1} = a_{1} - 0.3 \\ a_{2} = - 1 - 0.3 \\ a_{2} = - 1.3$

d=-1,3-(-1)=0,3

$a _{n} = a _{1} + d(n - 1) \\ a_{7} = - 1 - 0.3(7 - 1) \\ a_{7} = - 1 - 0.3 \times 6 \\ a_{7} = - 1 - 1.8 \\ a_{7} = -2.8$

3)

$b_{1 + 1} = 0.5b_{1} \\ b_{2} = 0.5 \times (- 16) \\ b_{2} = - 8$

$q = \frac{ - 8}{ - 16} = \frac{1}{2}$

$b_{ n } = b_{1} \times {q}^{n - 1} \\ b_{5} = - 16 \times {( \frac{1}{2} )}^{5 - 1} \\ b_{5} = - 16 \times \frac{1}{16} \\ b_{5} = - 1$

4)

$q = \frac{0.24}{ - 0.2} = \frac{6}{25} \div ( - \frac{1}{5} ) = \frac{6}{25} \times ( - 5) = - \frac{6}{5} = - 1.2$