y=ln[arctan(1-x)],这dy=
问题描述：
y=ln[arctan(1-x)],这dy=
答
y'=1/arctan(1-x)*1/[1+(1-x)²]*(1-x)'
=-1/[(x²-2x+2)arctan(1-x)]
所以
dy=-1/[(x²-2x+2)arctan(1-x)]dx