设方程x-y=ey确定隐函数y=f(x)

xy+e^y=y+1（1）求d^2y/dx^2在x=0处的值：（1）两边分别对x求导：y+xy'+e^yy'=y'y/y'+x+e^y=1(2)(2)两边对x再求导一次：(y'y'-yy'')/y'^

左右对x求导有y'/y=sec²(xy)(y+xy')整理有y'=y²/(cos(xy)-xy)所以dy=(y²/(cos(xy)-xy))dx

lny+x/y=0等式两边求导：y'*1/y+1/y+x*y'(-1/y²)=0(1/y-x/y²)y'=-1/y∴y'=(-1/y)/(1/y-x/y²)=-y/(y-

由隐函数微分法可得：－sin(x＋y)(1＋y′)＋y′＝0－sin(x＋y)＋[1－sin(x＋y)]y′＝0∴y′＝sin(x＋y)／[1－sin(x＋y)]．

y=1+xe^y两边对x求导得y'=e^y+xe^y*y'（是对x求导那么e^y就是一个复合函数了所以最后要在对y求导）(1-xe^y)y'=e^y∴y'=e^y/(1-xe^y)再问：还不是很明白这

这个题目要用到微分的形式不变性e^y*dy+d(xy)=0e^y*dy+xdy+ydx=0-ydx=(x+e^y)dydy=-y*dx/(x+e^y)

ln(x²+y²)=x+y-1两边对x求导得：(2x+2yy')/(x²+y²)=1+y'整理得：y'=(2x-x²-y²)/(x²

已知z=z(x,y)是由方程sinz=xyz所确定的隐函数.对sinz=xyz方程两边同对x求偏导,于是有cosz*（əz/əx）=yz+xy*(əz/əx).

网上有很多高数课后习题答案,你可以下载一个参考~e^y-e^x=xy两边求导,得e^y*y'-e^x=y+xy'(e^y-x)y'=(e^x+y)所以y'=(e^x+y)/(e^y-x)x=0时,原式

分别对y求导,求左边为1+【e^(x+y）×（dx/dy+1）】右边为2×dx/dy推的dx/dy：自己算下,没得草稿纸.

dz=-dx-dy

再问：你是用对数求导法么？第一步右边那个怎么写得出来的再答：

e^y-e^x=xy两边求导,得e^y*y'-e^x=y+xy'(e^y-x)y'=(e^x+y)所以y'=(e^x+y)/(e^y-x)x=0时,e^y-e^0=0,则e^y=1,则y=0所以y'(

ln(x+y)=x·lny(1+y‘)/(x+y)=lny+x/y·y‘y+y·y‘=y(x+y)lny+x(x+y)·y‘y‘=【y(x+x)lny-y】/【y-x(x+y)】再问：лл����

/>e^y+xy+e^x=0两边同时对x求导得：e^y·y'+y+xy'+e^x=0得y'=-(y+e^x)/(x+e^y)y''=-[(y'+e^x)(x+e^y)-(y+e^x)(1+e^y·y'

e^(x+y)+sin(xy)=1e^(x+y)*(1+y')+cos(xy)(y+xy')=0y'*[e*(x+y)+xcos(xy)]=-[ycos(xy)+e^(x+y)]y'=-[ycos(x

主要利用复合函数的求导：z=f(y),y=g(x),则z对x求导dz/dx=f'(y)*(dy/dx).等式左边对x求导过程：d(lny)/dx=(1/y)y',等式右边对x求导过程：d(x-y)/d

F(x,y)=x^2+y^2-ln(x+2y)Fx=2x-1/(x+2y)Fy=2y-2/(x+2y)F(x)=-Fx/Fy=-[2x(x+2y)-1]/[2y(x+2y)-2]

化为：e^(ylnx)-e^y=sin(xy)两边对x求导：e^(ylnx)(y'lnx+y/x)-y'e^y=cos(xy)(y+xy')y'[lnxe^(ylnx)-e^y-xcos(xy)]=[