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55) $lim_{x ightarrow -infty}\frac{5x^{3}+4x^{2}}{x - 5x^{2}}$ 56) $lim…

Question

  1. $lim_{x

ightarrow -infty}\frac{5x^{3}+4x^{2}}{x - 5x^{2}}$

  1. $lim_{x

ightarrow-infty}\frac{-6+(2/x)}{7-(1/x^{2})}$

  1. $lim_{x

ightarrow-infty}\frac{cos 3x}{x}$

  1. $lim_{x

ightarrowinfty}\frac{-5sqrt{x}+x - 1}{-4x + 2}$

  1. $lim_{x

ightarrowinfty}\frac{3x^{-1}+-2x^{-3}}{3x^{-2}+x^{-5}}$

  1. $lim_{x

ightarrow-infty}\frac{sqrt3{x}+5x+-5}{3x + x^{2/3}+-4}$

Explanation:

Response
55)

Step1: Divide numerator and denominator by highest - power of x in denominator

Divide both the numerator and denominator of $\frac{5x^{3}+4x^{2}}{x - 5x^{2}}$ by $x^{2}$. We get $\lim_{x
ightarrow-\infty}\frac{5x + 4}{\frac{1}{x}-5}$.

Step2: Evaluate the limit

As $x
ightarrow-\infty$, $\frac{1}{x}
ightarrow0$. So, $\lim_{x
ightarrow-\infty}\frac{5x + 4}{\frac{1}{x}-5}=-\infty$.

Step1: Use limit properties

We know that $\lim_{x
ightarrow-\infty}\frac{-6+\frac{2}{x}}{7-\frac{1}{x^{2}}}$. As $x
ightarrow-\infty$, $\lim_{x
ightarrow-\infty}\frac{2}{x}=0$ and $\lim_{x
ightarrow-\infty}\frac{1}{x^{2}} = 0$.

Step2: Substitute the limit values

Substituting these values into the expression, we get $\frac{-6 + 0}{7-0}=-\frac{6}{7}$.

Step1: Apply the Squeeze Theorem

We know that $- 1\leqslant\cos(3x)\leqslant1$. Then $\frac{-1}{x}\leqslant\frac{\cos(3x)}{x}\leqslant\frac{1}{x}$.

Step2: Evaluate the limits of the bounding functions

As $x
ightarrow-\infty$, $\lim_{x
ightarrow-\infty}\frac{-1}{x}=0$ and $\lim_{x
ightarrow-\infty}\frac{1}{x}=0$. By the Squeeze Theorem, $\lim_{x
ightarrow-\infty}\frac{\cos(3x)}{x}=0$.

Answer:

$-\infty$

56)