a) Since both limits are <em>distinct</em> and do not exist, we conclude that x = - 1 is not part of the domain of the <em>rational</em> function.
b) The function
is equivalent to the function
.
<h3>How to determine whether a limit exists or not</h3>
According to theory of limits, a function f(x) exists for x = a if and only if
. This criterion is commonly used to prove continuity of functions.
<em>Rational</em> functions are not continuous for all value of x, as there are x-values that make denominator equal to 0. Based on the figure given below, we have the following <em>lateral</em> limits:
![\lim_{x \to -1^{-}} \frac{x}{x^{2}+x} = - \infty](https://tex.z-dn.net/?f=%5Clim_%7Bx%20%5Cto%20-1%5E%7B-%7D%7D%20%5Cfrac%7Bx%7D%7Bx%5E%7B2%7D%2Bx%7D%20%3D%20-%20%5Cinfty)
![\lim_{x \to -1^{+}} \frac{x}{x^{2}+x} = + \infty](https://tex.z-dn.net/?f=%5Clim_%7Bx%20%5Cto%20-1%5E%7B%2B%7D%7D%20%5Cfrac%7Bx%7D%7Bx%5E%7B2%7D%2Bx%7D%20%3D%20%2B%20%5Cinfty)
Since both limits are <em>distinct</em> and do not exist, we conclude that x = - 1 is not part of the domain of the <em>rational</em> function.
In addition, we can simplify the function by <em>algebra</em> properties:
![\frac{x}{x^{2}+ x} = \frac{x}{x\cdot (x + 1)} = \frac{1}{x + 1}](https://tex.z-dn.net/?f=%5Cfrac%7Bx%7D%7Bx%5E%7B2%7D%2B%20x%7D%20%3D%20%5Cfrac%7Bx%7D%7Bx%5Ccdot%20%28x%20%2B%201%29%7D%20%3D%20%5Cfrac%7B1%7D%7Bx%20%2B%201%7D)
![g(x) = \frac{1}{x + 1}](https://tex.z-dn.net/?f=g%28x%29%20%3D%20%5Cfrac%7B1%7D%7Bx%20%2B%201%7D)
The function
is equivalent to the function
.
To learn more on lateral limits: brainly.com/question/21783151
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