Answer:
[tex]\text Explicit \ Formula :\ a_{n}= 1000\times (\frac{1}{5}) ^{n-1}[/tex]
Step-by-step explanation:
Let [tex]\left( a_{n}\right)[/tex] be our geometric sequence
The explicit formula for [tex]\left( a_{n}\right)[/tex] is :
[tex]a_{n}= a_1\times r^{n-1}[/tex]
where r is the common ratio
a1 is the first term
We notice that :
200/1000 = 1/5
40/200 = 1/5
⇒ r = 1/5
[tex]a_1 = 1000\ \ (given)[/tex]
Conclusion:
[tex]a_{n}= 1000\times (\frac{1}{5}) ^{n-1}[/tex]
