求高数大神帮帮忙

求高数大神帮帮忙4个题,谢谢啦!
2025-05-10 18:09:46
推荐回答(2个)
回答1:


回答2:

先整理,ln(x²+y²)=2arctan(x/y),
再求导,
(2x+2yy')/(x²+y²)=2((y-xy')/y²)/(1+(x/y)²)
x+yy'=y-xy'
y'=(y-x)/(y+x)