求z=arctanx的全微分-搜答案-智慧作业帮

我来试试吧...z=e^xy*cos(x+y)Z'x=ye^xycos(x+y)-e^xysin(x+y)Z'y=xe^xycos(x+y)-e^xysin(x+y)故dZ=[ye^xycos(x+y

Z=e^xy在x处的导函数为ye^(xy)在y处的导函数为xe^(xy)dz=ye^(xy)dx+xe^(xy)dy=2e^2dx+e^2dy

z=3x²y+x/yzx=6xy+1/yzy=3x²-x/y²所以dz=zxdx+zydy=(6xy+1/y)dx+(3x²-x/y²)dy

两边即对数得：lnz=xy*ln(lnu),不妨记u=x^2+y^2z'x/z=yln(lnu)+2x^2y/lnu,z'x=z[yln(lnu)+2x^2y/lnu]z'y/z=xln(lnu)+2

zx=1/(1+(x/y)²)*1/y=y/(x²+y²)zy=1/(1+(x/y)²)*(-x/y²)=-x/(x²+y²)所以

dz=2e^(2x+y^2)dx+2ye^(2x+y^2)dy把对x和对y的偏导分别求了出来再乘以各自的微分项即可.

u'x=2x/(x^2+y^2+z^2)u'y=2y/(x^2+y^2+z^2)u'z=2z/(x^2+y^2+z^2)du=2xdx/(x^2+y^2+z^2)+2ydy/(x^2+y^2+z^2)

z=1/2*ln(x^2+y^2+4)Z'x=1/2*1/(x^2+y^2+4)*(2x)=x/(x^2+y^2+4)Z'y=1/2*1/(x^2+y^2+4)*(2y)=y/(x^2+y^2+4)所

dz=1/y/(1+x^2/y^2)*dx-x/y^2/(1+x^2/y^2)*dy

dz=1/(1+(x/1+y^2)^2)*(dx/1+y^2)-1/(1+(x/1+y^2)^2)*x*(2ydy/1+y^2)^2

先求出z对x和y的偏导数分别是1/y,-x/y^2所以dz=(1/y)*dx-(x/y^2)*dy

2^(x^2+y^2)*In2*(2xdx+2ydy)

对等式两边求全微分du=【1/(2x+3y+4z^2)】【2dx+3dy+8zdz】

dz=x的偏导数乘德尔塔x+y的偏导数乘德尔塔y这是最基础的题呀,直接套公式啊

先求偏导数：zx=ycos(x-y)zy=sin(x-y)-ycos(x-y)明显,两偏导数都连续故全微分存在dz=zxdx+zydy=ycos(x-y)dx+[sin(x-y)-ycos(x-y)]

dz=2xydx+x^2dy再问：有全过程吗再答：en我想知道这里的X^2Y是指的X得平方乘以Y吗？如果是过程如下：dz/dx=2xydz/dy=x^2dz=2xydx+x^2dy再问：是X的2Y次方

dz=(y+1/y)dx+(x-x/y^2)dy

再问：就是这个吗？再答：是的。如还有不懂请追问，懂了请采纳。再问：还有这三题