Suppose the nth term of a series is 1+n2+n221+n2+n2 2. If there are 20 terms in the series, then the sum of the series is eal to

examrobotsa's picture
Q: 79 (CAPF/2021)
Suppose the nth term of a series is 1+n2+n221+n2+n2
2. If there are 20 terms in the series, then the sum of the series is eal to

question_subject: 

Logic/Reasoning

question_exam: 

CAPF

stats: 

0,1,4,0,2,2,1

The given series is 1+n2+n221+n2+n2 2.

To find the sum of the series, we need to substitute the value of n as 1, 2, 3, and so on until 20, and then add up all the terms.

Substituting n = 1:

1+(1^2)+(1^2^2) = 1+1+1 = 3

Substituting n = 2:

1+(2^2)+(2^2^2) = 1+4+16 = 21

Substituting n = 3:

1+(3^2)+(3^2^2) = 1+9+81 = 91

And so on, until we substitute n = 20.

Adding up all the terms, we get:

3 + 21 + 91 + ... + term 20

To simplify the calculation, we can observe that each term of the series has the form 2n^2 - 1.

Therefore, the series can be written as:

2(1^2) - 1 + 2(2^2) - 1 + 2(3^2) - 1