Question

Find the eighth term of P.G 1,2,4,8

Answer 1

$a_n=2^{n-1}\\\\a_1=2^{1-1}=2^0=1\\\\a_2=2^{2-1}=2^1=2\\\\a_3=2^{3-1}=2^2=4\\\\a_4=2^{4-1}=2^3=8\\\vdots\\a_{8}=2^{8-1}=2^7=128$

Answer 2

the answer is 128, the pattern is multiplying the previous number by 2 so example: 2x2=4 4x2=8 etc.