当x->+∞时，极限值为无穷大； 当x->-∞时，极限值为-50；
求解lim x[(x^2+100)^(1/2)+x]的值。x趋近于负无穷大。
limx*[(x^2+100)^(1/2)+x]
=lim(-x)*[(x^2+100)^(1/2)-x]
=lim{(-x)*[(x^2+100)^(1/2)-x]*[(x^2+100)^(1/2)+x]}/[(x^2+100)^(1/2)+x]
=lim{(-x)*[(x^2+100)-x^2]}/[(x^2+100)^(1/2)+x]
=lim(-100x)/[(x^2+100)^(1/2)+x]
=lim(-100)/{[1+(100/x^2)]^(1/2)+1}
=(-100)/[(1+0)^(1/2)+1]
=-50
这个极限明显是+∞
答：l i m x［(x^2+100)^1/2+x］= x→-∞ =l i m 100x/［(x^2+100)^1/2-x］= x→-∞ =l i m 100/[-...详情>>
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