Write the first five terms of the following sequences whose nth terms are:
an = (−1)n 2n
Advertisement Remove all ads
Solution
an = (−1)n 2n
Here, the nth term is given by the above expression. So, to find the first term we use n = 1 we get
`a_1 = (-1)^1.2^(1)`
= (-1).2
= -2
Similarly, we find the other four terms,
Second term (n = 2)
`a_2 = (-1)^2.2^2`
= 1.4
= 4
Third term (n = 3)
`a_3 = (-1)^3 . 2^3`
= (-1).8
= -8
Fourth term (n = 4)
`a_4 = (-1)^4 . 2^4`
= 1.16
= 16
Fifith term (n = 5)
`a_3 = (-1)^5 . (2)^5`
= (-1). 32
= -32
Therefore, the first five terms of the given A.P are `a_1 = -2, a_2 = 4, a_3 = -8, a_4 = 16, a_5 = -32`
Concept: nth Term of an AP
Is there an error in this question or solution?
Advertisement Remove all ads
APPEARS IN
Advertisement Remove all ads
Advertisement Remove all ads