例1:求下列极限 (1)m(-2+-)(2)im 3n-2 n-o n 2n2+n 3n3+ m 3n2+2 2n4-n 解:n2+n 2+ lim (2 n→ n→0 3n2+2 n→ 2 3+ lim( 3+ lim 2+ li n→00 n2n_2+02 lim 3+1 23+03例1：求下列极限 ) 1 2 (1) lim ( 2 n n n + → 3 2 2 (3) lim 2 2 n + + → n n n n 3n 2 (2) lim n − → 4 2 3 n 2 3 (4) lim n n n n − + → 2 2 2 2 2 1 1 2 lim(2 ) 2 : (3) lim lim 3 2 2 2 3 lim(3 ) 1 lim 2 lim 2 0 2 . 2 3 0 3 lim 3 lim n n n n n n n n n n n n n n n n n →  → → →  → → → → + + + = = + + + + + = = = + + 解 10