Question

Find the 13th term of geometric sequence 4,-16,64,...

Answer 1

Answer:

$a = 4$

$r = \frac{-16}{4}$

$r = -4$

$a_{13} = 4×(-4)^{(13-1)}$

$a_{13} = 4×(-4)^{12}$

$a_{13} = 4×16777216$

$a_{13} = 67108864$