这题极限怎么算,看不懂
来源:学生作业帮 编辑:搜搜做题作业网作业帮 分类:数学作业 时间:2024/08/11 22:18:45
这题极限怎么算,看不懂
![](http://img.wesiedu.com/upload/4/7e/47e157dc63a9ca650ac006a4878504d3.jpg)
![](http://img.wesiedu.com/upload/4/7e/47e157dc63a9ca650ac006a4878504d3.jpg)
![这题极限怎么算,看不懂](/uploads/image/z/714090-66-0.jpg?t=%E8%BF%99%E9%A2%98%E6%9E%81%E9%99%90%E6%80%8E%E4%B9%88%E7%AE%97%2C%E7%9C%8B%E4%B8%8D%E6%87%82)
x-->-1时,分母极限为0,则分子极限必为0
可得:-1-a+1+4=0,解得a=4
原极限变为:lim[x-->-1] (x³-4x²-1+4)/(x+1)
=lim[x-->-1] (x²(x-4)-(x-4))/(x+1)
=lim[x-->-1] (x²-1)(x-4)/(x+1)
=lim[x-->-1] (x-1)(x+1)(x-4)/(x+1)
=lim[x-->-1] (x-1)(x-4)
=10
因此b=10
可得:-1-a+1+4=0,解得a=4
原极限变为:lim[x-->-1] (x³-4x²-1+4)/(x+1)
=lim[x-->-1] (x²(x-4)-(x-4))/(x+1)
=lim[x-->-1] (x²-1)(x-4)/(x+1)
=lim[x-->-1] (x-1)(x+1)(x-4)/(x+1)
=lim[x-->-1] (x-1)(x-4)
=10
因此b=10