Question

Find a6 of the geometric sequence: a1=4 and a3=36

Answer 1

Geometric sequence

an=a1(r)^(n-1)
so

given
a1=4
and a3=36

36=a3=4(r)^(3-1)
36=4(r)^2
9=r^2
3=r


an=4(3)^(n-1)
a6 is
a6=4(3)^(6-1)
a6=4(3)^5
a6=4(243)
a6=972

a6=972