Question

Find an explicit rule for the nth term of the sequence.

-4, -8, -16, -32, ...

Answer 1

well... if we were to.... find what number is being used to get the "next" term... what do you think it might be?

Answer 2

-64

Answer 3

hmm well. yes... that means we're multiplying the current one by 2 to get the next one

thus 2 is our "common ratio" or "r"
the 1st term or \(\bf a_1\) is -4 in the sequence..... thus
\(\bf \large a_{\color{brown}{ n}}=a_1\cdot {\color{blue}{ r}}^{{\color{brown}{ n}}-1}\qquad a_1=-4\quad {\color{blue}{ r}}=2\qquad a_{\color{brown}{ n}}=-4\cdot {\color{blue}{ 2}}^{{\color{brown}{ n}}-1}\)

Answer 4

thank you, could you help me with more?

Answer 5

sure, is easier if you post anew...thus if I dunno, someone else may know and we can also revise each other

Answer 6

i'm new to open study, do i @tag you?