SNS

ANS NOT KNOWN.
PLS SOLVE.

@ABCDMAABCDMA !
I am getting this no option is matched please check if any mistake.

@KanishkKumar0
Summation is from n=2 to infinity
. I think you have taken n =1 to infinity.
Using n =2 the value of 20 L comes out to be 22

@RithvikSubash Yeah you are right . Sorry my mistake.