Q.

limn→∞∑k=1n-1(k-1)(nk-k2)2∑r=1nr3-∑s=0n(s2+(n-s)2)=t then [43t]=____  ([.] denotes GIF)


Ans.

(7)

Required=limn→∞3{∑r=1n-1(-r3+r2(n+1)-nr)}n(n+1)(3n2-n-2)=16