Question

the nth element of the sequence -1,2,-4,8……is​

Answer 1

Answer:

-16. I think this is the correct

Answer 2

Step-by-step explanation:

$given \ sequence, \\ -1,2,-4,8,........ \\\\ it \ is \ GP \\\\common \ ratio,r = \frac{2}{-1}=\frac{-4}{2}=\frac{8}{-4} =-2 \\ first \ term,a=-1 \\\\ n^{th} \ term \ of \ GP ,T_n=ar^{n-1} \\ T_n=(-1)(-2)^{n-1} \\ T_n=-(-2)^{n-1} \\\\ substitue \ the \ value \ of \ n \ for \ which \ you \ have \ to find \ the \ term \\\\ =>example : \\ if \ you \ have\ to \ find \ seventh \ term,put \ n=7 \\\\ T_n=-(-2)^{7-1} \\ T_n=-(-2)^6 \\T_n=-(64) \\ T_n=-64 \\ \boxed{seventh \ term \ is \ -64}$