lim x→1 (x³-3x+2)/(1-x²)麻烦给写下过程
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lim x→1 (x³-3x+2)/(1-x²)麻烦给写下过程
lim x→1 (x³-3x+2)/(1-x²)
麻烦给写下过程
lim x→1 (x³-3x+2)/(1-x²)麻烦给写下过程
x³-3x+2=(x³-x)-(2x-2)=x(x^2-1)-2(x-1)=x(x+1)(x-1)-2(x-1)=(x-1)(x^2+x-2)
lim x→1 (x³-3x+2)/(1-x²)=lim x→1 (x-1)(x^2+x-2)/(1-x)(1+x)
=lim x→1 -(x^2+x-2)/(1+x)=0
用罗比达法则:
lim
=lim
=3×(1-1)/(-2×1)
=0.