How can a function g(x) be defined so that g(x) is continuous for all x, and so that g(x) = f(x) except for where f(x) is discontinuous?
f(x) is discontinuous at 1

How can a function gx be defined so that gx is continuous for all x and so that gx fx except for where fx is discontinuous fx is discontinuous at 1 class=

Respuesta :

Answer:

[tex]g(x)=\begin{cases}f(x) \ \ \text{ if } \ x \ne 1\\ -1 \ \ \ \ \text{ if }\ x=1\end{cases}[/tex]

Step-by-step explanation:

We are given the function:

[tex]f(x) = \dfrac{x^2-3x+2}{x-1}[/tex]

and know that it has a removable discontinuity (undefined point) at x = 1.

We are trying to replicate this function in [tex]g(x)[/tex] using a piecewise definition while removing its discontinuity at x = 1.

[tex]g(x)=\begin{cases}f(x) \ \ \text{ if } \ x \ne 1\\ ? \ \ \ \ \ \ \,\text{ if }\ x=1\end{cases}[/tex]

To solve for out the y-value that would make f(x) continuous at x = 1, we can take the limit of the function as it approaches that x-value:

[tex]? = \displaystyle \lim_{x\,\to \,1}f(x)[/tex]

[tex]\displaystyle = \lim_{x\,\to \,1}\!\left(\dfrac{x^2-3x+2}{x-1}\right)[/tex]

↓ factoring the numerator

[tex]\displaystyle = \lim_{x\,\to \,1}\!\left(\dfrac{(x-2)(x-1)}{x-1}\right)[/tex]

↓ canceling the [tex](x-1)[/tex] that appears in both the numerator and denominator of the fraction

[tex]\displaystyle = \lim_{x\,\to \,1}(x-2)[/tex]

↓ evaluating the limit

[tex]= 1 - 2[/tex]

↓ executing the subtraction

[tex]= - 1[/tex]

So, the piecewise definition for [tex]g(x)[/tex] is:

[tex]\boxed{g(x)=\begin{cases}f(x) \ \ \text{ if } \ x \ne 1\\ -1 \ \ \ \ \text{ if }\ x=1\end{cases}}[/tex]