The second and eighth terms of a geometric sequence are 3 and 192, respectively. find the first term, common ratio, and an explicit rule for the nth term.
To solve the question we proceed as follows: The explicit formula for geometric series is given by: nth=ar^(n-1) where: a=first term n=number of terms second term is: 3=ar(2-1) 3=ar thus a=3/r
also the 8th term will be: 192=ar^(8-1) 192=ar^7 substituting the value of a in the above we get: 192=(3/r)r^7 this will give us 64=r^6 thus r=2 hence the value of a will be: a=3/2=1.5
