Ozdzx例3设z=arcsinaydxOzX解ax+y+y(y=ly)Iyl/(x2+ y)3I y/r+y
例 3 设 2 2 arcsin x y x z + = ,求 x z , y z . 解 = x z + + − x x y x x y x 2 2 2 2 2 1 1 2 2 3 2 2 2 | | (x y ) y y x y + + = . | | 2 2 x y y + = ( | |) 2 y = y
az.xay(-xy)V(x*+ y)3Iyl1x(y#0)sgn2y1az不存在。ayx*0y=0
= y z + + − y x y x x y x 2 2 2 2 2 1 1 2 2 3 2 2 ( ) ( ) | | x y xy y x y + − + = x y y x 1 sgn 2 2 + = − ( y 0) 0 0 = y y x z 不存在.
例4已知理想气体的状态方程pV=RTavaTap(R为常数),求证::-1.avaTopRTopRT证p=U2VavavRRTaTVpVVTRapaTRppaTavRTRVRTap -1.V2aTopRpVavp
例 4 已知理想气体的状态方程pV = RT (R为常数),求证: = −1 p T T V V p . 证 = V RT p ; 2 V RT V p = − = p RT V ; p R T V = = R pV T ; R V p T = = p T T V V p 2 V RT − p R R V = −1. pV RT = −