In: Math
A geometric sequence has the first term a1 = −3 and common ratio r = 1/2 . What is the 8th term?
Consider a geometric sequence with first term a1 = -3 and common ratio r = 1/2
Use the formula for nth term of a geometric sequence,,
an = a1 ∙ rn-1 ...... (1)
Substitute a1 = -3, r = 1/2 and n = 8 in the formula (1) and compute 8th term of given sequence,
a8= -3 × (1/2)8-1
= -3 × 1/128
= -3/128
Therefore, 8th term of given sequence is a3 = -3/128.
Therefore, 8th term of given sequence is a3 = -3/128.