Tính I=limx→+∞x3+2x23−x2−2x.

Đáp án đúng là: A

I=limx→+∞x3+2x23−x2−2x=limx→+∞x3+2x23−x+1+x−1−x2−2x=limx→+∞x3+2x23−x+1x3+2x232+x3+2x23x−1+x−12x3+2x232+x3+2x23x−1+x−12+limx→+∞x−1−x2−2xx−1+x2−2xx−1+x2−2x=limx→+∞x3+2x2−x−13x3+2x232+x3+2x23x−1+x−12+limx→+∞x−12−x2−2xx−1+x2−2x=limx→+∞5x2−3x+1x3+2x232+x3+2x23x−1+x−12+limx→+∞1x−1+x2−2x=51+1+1+0=53.