limit, differentiation

2011-08-20 4:16 am

1)lim x->-2 x^2-4/ x+2=?
2)lim x->3 2x^2-5x-3/ x-3=?
3) d/dx(2x^3-4x+e+ln4)=?
4) d/dx(7x^2-8 sqroot x +1) =?

thx a lot!

更新1:

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更新2:

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回答 (1)

myisland8132

2011-08-20 5:20 am

✔ 最佳答案

1) lim x->-2 (x^2-4)/(x+2)

= lim x->-2 (x-2)(x+2)/(x+2)

= -4

2)lim x->3 (2x^2-5x-3)/(x-3)

= lim x->3 (x-3)(2x+1))/(x-3)

= 7

3) d/dx(2x^3-4x+e+ln4)

= 6x^2-4

4) d/dx(7x^2-8 sqroot x +1)

= 14x - 4/√x

👍 0 👎 0

收錄日期: 2021-04-26 14:56:40
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