Question

Study the geometric sequence {-4, -84, -1764, -37044, ...}.

Answer 1

Answer:

              $\bold{a_n=(-4)21^{n-1}}$

Step-by-step explanation:

$a_1=-4\,,\ a_2=-84\,,\ a_3=-1764\,,\ a_4=-37044\quad\implies\ \ r=21$

{-84:(-4)=21 and -1764:(-84)=21 and -37044:(-1764)=21}

geometric sequence formula:   $a_n=a_1r^{n-1}$

$a_1=-4\quad and \ \ r=21$

$a_n=(-4)21^{n-1}$