Ageometric sequence is defined by the equation an = (4)3 − n. part a. what are the first three terms of the sequence? (1 point) part b. what is the value of r? part c. what is the value of a12?

A. an=4^(3-n)
a1= 4^(3-1) = 4^2 = 16
a2= 4^(3-2) =4^1 = 4
a3= 4^(3-3) = 4^0 = 1
b. r= 1/4 (you can see from what I prove in the picture or from part a
an= a1r^(n-1)
4 = 16(r)^(2-1)
4 = 16(r)
so r = 4/16 = 1/4
c. a12=a1r^(n-1)
=16(1/4)^(12-1)
=16(1/4)^11
=16/ 4^11
=16/4194304
=3.81*10^(-5)