Question

A geometric series has first term 4 and common ration is 1/2. Find 20th term of series

Answer 1

Step-by-step explanation:

first term = 4

common ratio = 1/2

tn = a×r^(n-1)

$t20 = 4 \times { (\frac{1}{2}) }^{20 - 1} \\ = {2}^{2} \times \frac{1}{ {2}^{19} } \\ = {2}^{2} \times {2}^{ - 19} \\ = {2}^{2 - 19} \\ = {2}^{ - 17} \\ = \frac{1}{ {2}^{17} }$

therefore the 20th term is = 1/2^17

hope you get your answer