例11求极限im 2x+3 x→>∞2x+1 2x+3x=m(1+ 解im(2+1) 2x+1 2x+1 (1+ 2 lim(1+)2=lim (1+ e例11 ) 1 (1 ) 1 (1 lim t t t t + + = → ) . 2 1 2 3 lim( x x x x + + → 2 1 ) 1 lim(1 2 2 1 − → = = + + t t t t x x x x ) 2 1 2 lim(1 + = + → = e. 求极限 解 x x x x ) 2 1 2 3 lim( + + →