例1、设z=f(x,y)= e sin y,x=st,y az az 求 as ot 解:z2.x az a as ax as ay as e sin y·t+e"cosy =te(sin Cos SS S azaz ax az ay 十 at ax at ay at e sin y·s+ e cos y =e ( ssin-t-cos 2012/2/192012/2/19 4 z x z y x t y t             sin x   e y s 1 ( sin cos ) st t t e s s s s   . t y s 例 1、设 ( , ) sin ,  x z f x y e y   x st  , , zs  . zt  求 解： z x z y x s y s             sin x  e y 21 (sin cos ) st t t te s s s   t cos x e y 2 ( ) ts   1 cos x e y s   zs zt 