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Find $$\lim_{x \to 2}\frac{x^3+3x^2-12x+4}{x^3-4x}$$ How do you get to your solution? Thanks in advance. I have tried factoring out $x^3$ to no avail.

Is there an algebraic solution? I don't know L'H rule.

3 Answers3

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Divide top and bottom by $x-2$, and then substitute in $x=2$.

Trogdor
  • 10,331
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$$\lim_{x \to 2}\frac{x^3+3x^2-12x+4}{x^3-4x}=\lim_{x \to 2}\frac{(x-2)(x^2+5x-2)}{x(x+2)(x-2)}=3/2$$

ketan
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$$\lim_{x \to 2}\frac{x^3+3x^2-12x+4}{x^3-4x}=\lim_{x \to 2}\frac{3x^2+6x-12}{3x^2-4}=\dfrac{3}{2}$$ In the second step, I used L'Hopital's rule.