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(4-x^3)/x^2

Limit of the function (4-x^3)/x^2

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     /     3\
     |4 - x |
 lim |------|
x->oo|   2  |
     \  x   /
$$\lim_{x \to \infty}\left(\frac{4 - x^{3}}{x^{2}}\right)$$
Limit((4 - x^3)/x^2, x, oo, dir='-')
Detail solution
Let's take the limit
$$\lim_{x \to \infty}\left(\frac{4 - x^{3}}{x^{2}}\right)$$
Let's divide numerator and denominator by x^3:
$$\lim_{x \to \infty}\left(\frac{4 - x^{3}}{x^{2}}\right)$$ =
$$\lim_{x \to \infty}\left(\frac{-1 + \frac{4}{x^{3}}}{\frac{1}{x}}\right)$$
Do Replacement
$$u = \frac{1}{x}$$
then
$$\lim_{x \to \infty}\left(\frac{-1 + \frac{4}{x^{3}}}{\frac{1}{x}}\right) = \lim_{u \to 0^+}\left(\frac{4 u^{3} - 1}{u}\right)$$
=
$$\frac{-1 + 4 \cdot 0^{3}}{0} = -\infty$$

The final answer:
$$\lim_{x \to \infty}\left(\frac{4 - x^{3}}{x^{2}}\right) = -\infty$$
Lopital's rule
We have indeterminateness of type
-oo/oo,

i.e. limit for the numerator is
$$\lim_{x \to \infty}\left(4 - x^{3}\right) = -\infty$$
and limit for the denominator is
$$\lim_{x \to \infty} x^{2} = \infty$$
Let's take derivatives of the numerator and denominator until we eliminate indeterninateness.
$$\lim_{x \to \infty}\left(\frac{4 - x^{3}}{x^{2}}\right)$$
=
$$\lim_{x \to \infty}\left(\frac{\frac{d}{d x} \left(4 - x^{3}\right)}{\frac{d}{d x} x^{2}}\right)$$
=
$$\lim_{x \to \infty}\left(- \frac{3 x}{2}\right)$$
=
$$\lim_{x \to \infty}\left(- \frac{3 x}{2}\right)$$
=
$$-\infty$$
It can be seen that we have applied Lopital's rule (we have taken derivatives with respect to the numerator and denominator) 1 time(s)
The graph
Rapid solution [src]
-oo
$$-\infty$$
Other limits x→0, -oo, +oo, 1
$$\lim_{x \to \infty}\left(\frac{4 - x^{3}}{x^{2}}\right) = -\infty$$
$$\lim_{x \to 0^-}\left(\frac{4 - x^{3}}{x^{2}}\right) = \infty$$
More at x→0 from the left
$$\lim_{x \to 0^+}\left(\frac{4 - x^{3}}{x^{2}}\right) = \infty$$
More at x→0 from the right
$$\lim_{x \to 1^-}\left(\frac{4 - x^{3}}{x^{2}}\right) = 3$$
More at x→1 from the left
$$\lim_{x \to 1^+}\left(\frac{4 - x^{3}}{x^{2}}\right) = 3$$
More at x→1 from the right
$$\lim_{x \to -\infty}\left(\frac{4 - x^{3}}{x^{2}}\right) = \infty$$
More at x→-oo
The graph
Limit of the function (4-x^3)/x^2