⑩天掌 Teaching Plan on Advanced Mathematics 例2作函数q(x)=e2的图形 √2兀 解D:(-∞,+0),W:0<9(x)≤=≈04 2兀 偶函数,图形关于y轴对称 φp(x) cp(x)= (x+1)(x-1) 2π 令q(x)=0,得驻点x=0, 令q"(x)=0,得特殊点x=-1,x=1 lim op(x)=lim e2=0 x→0 2π 得水平渐近线y=0 2004-4-10Tianjin Polytechnic University Teaching Plan on Advanced Mathematics 例2 . 2 1 ( ) 2 2 作函数 的图形 x x e −   = 解 D :(−,+), 偶函数,图形关于y轴对称. , 2 ( ) 2 2 x e x x −   = − 令 (x) = 0, 得驻点 x = 0, 令 (x) = 0, 得特殊点x = −1, x = 1. 0.4. 2 1 : 0 ( )   W   x  . 2 ( 1)( 1) ( ) 2 2 x e x x x −  + −  = − 2 2 2 1 lim ( ) lim x x x x e − → →    = = 0, 得水平渐近线 y = 0. 2004-4-10