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(-1-2*x+3*x^2)/(1+x^2+4*x)

Limit of the function (-1-2*x+3*x^2)/(1+x^2+4*x)

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The solution

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     /              2\
     |-1 - 2*x + 3*x |
 lim |---------------|
x->1+|       2       |
     \  1 + x  + 4*x /
$$\lim_{x \to 1^+}\left(\frac{3 x^{2} + \left(- 2 x - 1\right)}{4 x + \left(x^{2} + 1\right)}\right)$$
Limit((-1 - 2*x + 3*x^2)/(1 + x^2 + 4*x), x, 1)
Detail solution
Let's take the limit
$$\lim_{x \to 1^+}\left(\frac{3 x^{2} + \left(- 2 x - 1\right)}{4 x + \left(x^{2} + 1\right)}\right)$$
transform
$$\lim_{x \to 1^+}\left(\frac{3 x^{2} + \left(- 2 x - 1\right)}{4 x + \left(x^{2} + 1\right)}\right)$$
=
$$\lim_{x \to 1^+}\left(\frac{\left(x - 1\right) \left(3 x + 1\right)}{x^{2} + 4 x + 1}\right)$$
=
$$\lim_{x \to 1^+}\left(\frac{\left(x - 1\right) \left(3 x + 1\right)}{x^{2} + 4 x + 1}\right) = $$
$$\frac{\left(-1 + 1\right) \left(1 + 3\right)}{1 + 1^{2} + 4} = $$
= 0

The final answer:
$$\lim_{x \to 1^+}\left(\frac{3 x^{2} + \left(- 2 x - 1\right)}{4 x + \left(x^{2} + 1\right)}\right) = 0$$
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
One‐sided limits [src]
     /              2\
     |-1 - 2*x + 3*x |
 lim |---------------|
x->1+|       2       |
     \  1 + x  + 4*x /
$$\lim_{x \to 1^+}\left(\frac{3 x^{2} + \left(- 2 x - 1\right)}{4 x + \left(x^{2} + 1\right)}\right)$$
0
$$0$$
= 7.05349503376048e-31
     /              2\
     |-1 - 2*x + 3*x |
 lim |---------------|
x->1-|       2       |
     \  1 + x  + 4*x /
$$\lim_{x \to 1^-}\left(\frac{3 x^{2} + \left(- 2 x - 1\right)}{4 x + \left(x^{2} + 1\right)}\right)$$
0
$$0$$
= -4.21717804841302e-34
= -4.21717804841302e-34
Rapid solution [src]
0
$$0$$
Other limits x→0, -oo, +oo, 1
$$\lim_{x \to 1^-}\left(\frac{3 x^{2} + \left(- 2 x - 1\right)}{4 x + \left(x^{2} + 1\right)}\right) = 0$$
More at x→1 from the left
$$\lim_{x \to 1^+}\left(\frac{3 x^{2} + \left(- 2 x - 1\right)}{4 x + \left(x^{2} + 1\right)}\right) = 0$$
$$\lim_{x \to \infty}\left(\frac{3 x^{2} + \left(- 2 x - 1\right)}{4 x + \left(x^{2} + 1\right)}\right) = 3$$
More at x→oo
$$\lim_{x \to 0^-}\left(\frac{3 x^{2} + \left(- 2 x - 1\right)}{4 x + \left(x^{2} + 1\right)}\right) = -1$$
More at x→0 from the left
$$\lim_{x \to 0^+}\left(\frac{3 x^{2} + \left(- 2 x - 1\right)}{4 x + \left(x^{2} + 1\right)}\right) = -1$$
More at x→0 from the right
$$\lim_{x \to -\infty}\left(\frac{3 x^{2} + \left(- 2 x - 1\right)}{4 x + \left(x^{2} + 1\right)}\right) = 3$$
More at x→-oo
Numerical answer [src]
7.05349503376048e-31
7.05349503376048e-31
The graph
Limit of the function (-1-2*x+3*x^2)/(1+x^2+4*x)