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Given:
and
where
.
To find:
The explicit formula for the given recursive formula.
Solution:
We know that recursive formula of an AP is:

Where, d is the common difference.
We have,

Here, d=9.
The first term of the AP is
.
The explicit formula for an AP is:

Substituting
and
, we get



Therefore, the required explicit formula for the given sequence is
.
Square root of 16 because it equals to 4 which is a rational number
Answer:
20.3 units
Step-by-step explanation:
AB/CB = BD/AB
9/CB = 4/9
CB = 9×9/4
CB = 81/4 = 20¼ units
20.25 (20.3 units correct to 1 dp)