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A sequence is shown as follows:

points at (1,32), (2,8), (3,2), (4,0.5)

Assuming the pattern continues, what is the formula for the nth term?

User Viraj Tank
by
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1 Answer

6 votes

Answer: an = 128 * (1/4)^n

Explanation:

The given sequence is not an arithmetic or geometric sequence, but we can try to find a pattern using algebra. Let's assume that the formula for the nth term is of the form:

an = a * b^n

where a and b are constants to be determined. We can find these constants by using the first two points:

a * b^1 = 32 (when n = 1)

a * b^2 = 8 (when n = 2)

Dividing the second equation by the first, we get:

b^1 = (8/32) / (1/2) = 1/4

Substituting this value of b in the first equation, we get:

a * (1/4)^1 = 32

a = 128

Therefore, the formula for the nth term is:

an = 128 * (1/4)^n

We can check this formula using the other given points:

a2 = 128 * (1/4)^2 = 8

a3 = 128 * (1/4)^3 = 2

a4 = 128 * (1/4)^4 = 0.5

So the formula holds for all the given points.

User Nishant Tyagi
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