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Limit of the function/ 3*x

Limit of the function 3*x

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 lim  (3*x)
x->-oo

\lim_{x \to -\infty}\left(3 x\right)

Limit(3*x, x, -oo)

Detail solution

Let's take the limit

\lim_{x \to -\infty}\left(3 x\right)

Let's divide numerator and denominator by x:

\lim_{x \to -\infty}\left(3 x\right)

\lim_{x \to -\infty} \frac{1}{\frac{1}{3} \frac{1}{x}}

Do Replacement

u = \frac{1}{x}

then

\lim_{x \to -\infty} \frac{1}{\frac{1}{3} \frac{1}{x}} = \lim_{u \to 0^+}\left(\frac{3}{u}\right)

\frac{3}{0} = -\infty

The final answer:

\lim_{x \to -\infty}\left(3 x\right) = -\infty

Lopital's rule

There is no sense to apply Lopital's rule to this function since there is no indeterminateness of 0/0 or oo/oo type

The graph

Plot the graph

Rapid solution [src]

-oo

-\infty

Expand and simplify

Other limits x→0, -oo, +oo, 1

\lim_{x \to -\infty}\left(3 x\right) = -\infty

\lim_{x \to \infty}\left(3 x\right) = \infty

\lim_{x \to 0^-}\left(3 x\right) = 0

\lim_{x \to 0^+}\left(3 x\right) = 0

\lim_{x \to 1^-}\left(3 x\right) = 3

\lim_{x \to 1^+}\left(3 x\right) = 3

The graph