1
JEE Main 2021 (Online) 26th August Morning Shift
MCQ (Single Correct Answer)
+4
-1
The sum of the series

$${1 \over {x + 1}} + {2 \over {{x^2} + 1}} + {{{2^2}} \over {{x^4} + 1}} + ...... + {{{2^{100}}} \over {{x^{{2^{100}}}} + 1}}$$ when x = 2 is :
A
$$1 + {{{2^{101}}} \over {{4^{101}} - 1}}$$
B
$$1 + {{{2^{100}}} \over {{4^{101}} - 1}}$$
C
$$1 - {{{2^{100}}} \over {{4^{100}} - 1}}$$
D
$$1 - {{{2^{101}}} \over {{2^{400}} - 1}}$$
2
JEE Main 2021 (Online) 26th August Morning Shift
MCQ (Single Correct Answer)
+4
-1
If the sum of an infinite GP a, ar, ar2, ar3, ....... is 15 and the sum of the squares of its each term is 150, then the sum of ar2, ar4, ar6, ....... is :
A
$${5 \over 2}$$
B
$${1 \over 2}$$
C
$${25 \over 2}$$
D
$${9 \over 2}$$
3
JEE Main 2021 (Online) 25th July Morning Shift
MCQ (Single Correct Answer)
+4
-1
Let Sn be the sum of the first n terms of an arithmetic progression. If S3n = 3S2n, then the value of $${{{S_{4n}}} \over {{S_{2n}}}}$$ is :
A
6
B
4
C
2
D
8
4
JEE Main 2021 (Online) 22th July Evening Shift
MCQ (Single Correct Answer)
+4
-1
Let Sn denote the sum of first n-terms of an arithmetic progression. If S10 = 530, S5 = 140, then S20 $$-$$ S6 is equal to:
A
1862
B
1842
C
1852
D
1872
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