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y'=(X+Y)/(X-Y)的二阶导数怎么求?

题目详情
y'=(X+Y)/(X-Y)的二阶导数怎么求?
▼优质解答
答案和解析
y''=[(x+y)'(x-y)-(x+y)(x-y)']/(x-y)²
=[(1+y')(x-y)-(x+y)(1-y')]/(x-y)²
=2(xy'-y)/(x-y)²
然后将y'=(x+y)/(x-y)代入上式即可,下面自己算吧,如需我算,