List the first five terms of the sequence. an = (-1)n - 1 /4n.
Solution:
Given the f(n) = an = (-1)n - 1 /4n.
Let us take n = 1, 2, 3, 4, 5
When n = 1 ⇒ f(1) = a1 = (-1)1 - 1 / 41 = (-1)0 / 4 = 1/4 [ since any number power zero is 1]
When n = 2 ⇒ f(2) = a2 = (-1)2 - 1 / 42 = -1/16
When n = 3 ⇒ f(3) = a3 = (-1)3 - 1 / 43 = 1/64
When n = 4 ⇒ f(4) = a4 = (-1)4 - 1 / 44 = -1/256
When n = 5 ⇒ f(5) = a5 = (-1)5 - 1 / 45 = 1/1024
Since, even powers of -1 give ‘1’ and odd powers of -1 give ‘-1’.
Therefore, the first five terms of the sequence are 1/4, -1/16, 1/64, -1/256, 1/1024
List the first five terms of the sequence. an = (-1)n - 1 /4n.
Summary:
The first five terms of the sequence. an = (-1)n - 1 /4n are 1/4, -1/16, 1/64, -1/256, 1/1024.
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