f(x,y)=x平方arctany求微分 急

问题描述:

f(x,y)=x平方arctany求微分 急

af/ax=2xarctany
af/ay=x^2/(1+y^2)
所以df=af/ax*dx+af/ay*dy
=2xarctanydx+x^2/(1+y^2)dy