Question

lim(x→∞)[(x^2-2x+1)/(x+1)是分子分母同除以x还是x^2

Answer 1

此题不用同除

同除是除分子和分母中的最高次项,

即是不论分子分母,总之是最高次项

lim(x→∞)(x^2-2x+1)/(x+1)

=lim(x→∞)(x^2+x-3x-3+3+1)/(x+1)

=lim(x→∞)(x^2+x-3x-3+3+1)/(x+1)

=lim(x→∞)(x-3+4/(x+1))

=+∞+0

=+∞