lim(x-->0)(√(1-2x-x^2)-(1-x))/x
问题描述：
lim(x-->0)(√(1-2x-x^2)-(1-x))/x
答
上下乘√(1-2x-x^2)+(1-x)
分子是平方差
所以原式=lim(1-2x-x²-1+2x-x²)/x[√(1-2x-x^2)+(1-x)]
=-2limx/[√(1-2x-x^2)+(1-x)]
=0