If the sum of the first ten terms of the series 1 3 5 2 + 2 2 5 2 + 3 1 5 2 + 4 2 + 4 4 5 2 + … . , is…

If the sum of the first ten terms of the series 1352+2252+3152+42+4452+., is 165m , then m is equal to 
  1. 100
  2. 99
  3. 102
  4. 101

Solution

852+1252+1652 ........ upto ten terms

Tn=4n+452

Tn=16n2+2n+125

Tn=1625n2+2n+1

Sn=1625n2+2n+1

Sn=1625 nn+1 2n+16+2nn+12+n

Put n=10 

162510·11·216+2·10·112+10

=1625 385+110+10=1625· 505

=165·101

Hence m=101

Asked in: JEE Main 2016 (03 Apr)

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