To find the first three terms, substitute n =1 n= 2 n= 3 in to the equation
n=1 a(1) = 2^(5-2(1)) = 8
n=2 2
n=3 .5
to get the next term of a geometric sequence, you multiply the previous term by 'r'
r is the value used to multiply the 1st term by to get the 2nd term 8(x) = 2 x = 2/8 = 1/4
a(10) = 2^(5-2(10)) = 2^(-15) = 1/(2^(15)) = 1/ 32768 = .000030518