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JEE MATHEMATICS MCQ: PERMUTATIONS

1 Medium

1 of 1

Analyzing +4 | -1

S_n=1 !+2 !+3 !+4 !+\ldots+n !

cannot be the square of natural number except for

n

, is

View answer and explanation

Correct option: C

1, 3

The correct answer is C (1, 3) because

S_n

is a perfect square only for n=1 and n=3, and not for other values as the unit digit becomes 3 for n >= 5.

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