已知y=ln[(x+1)/(x-1)],求dy/dx

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已知y=ln[(x+1)/(x-1)],求dy/dx

已知y=ln[(x+1)/(x-1)],求dy/dx
已知y=ln[(x+1)/(x-1)],求dy/dx

已知y=ln[(x+1)/(x-1)],求dy/dx
应该这样
y=ln[(x+1)/(x-1)]
=ln(x+1)-ln(x-1)
再求导,得
y'=1/(x+1)-1/(x-1)
=-2/(x+1)(x-1) (可以不写)

dy/dx=y'={1/[(x+1)/(x-1)]}×[(x+1)/(x-1)]'
=[(x-1)/(x+1)][(x+1)'(x-1)-(x+1)(x-1)']/(x-1)²
=[(x-1)/(x+1)](x-1-x-1)/(x-1)²
=[(x-1)/(x+1)][(-2)/(x-1)²]
=(-2)(x-1)/[(x-1)²(x+1)]
=-2/[(x-1)(x+1)]
=-2/(x²-1)