Question

quantos termos tem uma PG cujo a1= 1/2, q= 2 e an= 128

Answer 1

an = a1 * q^n-1
128 = 1/2 * 2^n-1
2^n-1 = 128 / 1/2
2^n-1 = 128 * 2
2^n-1 = 256
2^n-1 = 2^8
n-1 = 8
n = 8 + 1
n = 9