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Write an explicit formula for an,the Nth term of the sequence 4,12,36

User Mbanda
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1 Answer

11 votes

Answer:


3^(n)+3^(n-1)

Explanation:

Since the sequence is geometric (it multiplies the previous number each time). The nth term sequence would be
x^n + yn

Because the sequence multiplies by 3 each time, The base number in that equation would be
3^n +yn.

So
3^n of the equation would be:

3, 9, 27.

Compare the 2 equations:
4, 12, 36

3, 9 ,27

The difference between the 2 equations is: 1, 3, 9 which itself is a geometric sequence so the nth term of this new equation is:
3^(n-1).

Combine these 2 equations together and you get:


3^(n)+3^(n-1).

User Jawad Ali
by
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