Q54 / 90 · JEE Main 2022 (27 Jul Shift 2) · Mathematics

23-131×7+43-33+23-132×11+63-53+43-33+23-133×15+…..+303-293+283-273+…+23-1315×63 is equal to ______.

Correct answer: 120

Solution

Given series, 23-131×7+43-33+23-132×11+63-53+43-33+23-133×15+…..+303-293+283-273+…+23-1315×63 

Now finding Tn=∑k=1n2k3-2k-13n4n+3

=∑k=1n4k2+2k-12+2k2k-1n4n+3

=∑k=1n12k2-6k+1n4n+3

=2n2n2+3n+1-3n2-3n+nn4n+3

=n24n+3n4n+3=n

So,Tn=n

Now finding Sn=∑n=115Tn=15×162=120

Hence, the correct answer is 120.

Relevant Questions