Question

计算：limn→∞(n+1)(1?3n)(2?n)(n2+n+1)=______

计算：limn→∞(n+1)(1?3n)(2?n)(n2+n+1)=______．

Answer 1

lim

n→∞

(n+1)(1?3n)

(2?n)(n2+n+1)

=

lim

n→∞

1 n (1+  1 n )( 1 n ?3)

( 2 n ?1)(1+ 1 n2 +  1 n )

=0
故答案为：0