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MathsMediumMCQ2025 ยท 28 Jan Shift 2

Q12.For positive integers n, if 4an = (n2 + 5n + 6) and Sn = โˆ‘nk=1 ( ak1 ), then the value of (1) 540 (2) 675 (3) 1350 (4) 135

What This Question Tests

This question involves recognizing a pattern in the given term `a_n`, decomposing it using partial fractions, and then finding the sum of the series using a telescopic sum approach.

Concepts Tested

Arithmetic Progression (A.P.)Partial fraction decompositionSummation of a series (telescopic sum)

Formulas Used

Partial fraction decomposition: 1/(n(n+1)) = 1/n - 1/(n+1)

Summation notation ฮฃ

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