Q.

Among

(S1):limn1n2(2+4+6++2n)=1

(S2):limn1n16(115+215+315++n15)=116              [2023]
 

1 Only (S1) is true  
2 Both (S1) and (S2) are false  
3 Only (S2) is true  
4 Both (S1) and (S2) are true  

Ans.

(4)

(S1): limn1n2(2+4+6++2n)

=limn1n2×2(1+2+3++n)

=limn1n2×2×n(n+1)2=limn(1+1n)=1

   (S1) is true.

(S2): limn1n16115+215+315++n15=limn1n16r=1nr15

=limn1nr=1n(rn)15=01x15dx=|x1616|01=116

  (S2) is also true.