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11 votes
11 votes
it says I'm supposed to graph each function and then right down the domain and range. I'm a remote student and I have no idea where to start on this

it says I'm supposed to graph each function and then right down the domain and range-example-1
User Emmanuel John
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2.6k points

1 Answer

24 votes
24 votes

Notice that this function is defined in two parts (piecewise function) depending on the value of the variable "x".

So first thing is to find on the x-axis of the graph the point at which the function changes denominations. Those points are x = -1, and x = 1 since notice that for x smaller than -1 you need to use the constant value "3' for the function, while for x larger than 1 (to the right of that value) you need to use the expression of a line "x + 1" which has slope "1" (one) and y-intercept "1" (one). In the middle, there is no definition for the function.

Therefore we are going to mark on the graph a division and expect different graphs to appear to the left and to the right of the x = -1, and to the left and right of "1":

Notice that to the left of x = -1 we have plotted a horizontal line which corresponds to a constant value of "3" units on the y-axis. Notice as well a little "empty circe" at the location where the x is -1 (this is because we cannot include the point f(-1), given that the funcyion is not defined there.

Now, to the right of x = 1 we have the line with slope 1 and which (if allowed) would cross the y-axis at y = 1. Notice as well a little "empty circle" for the value x=1 since the function is not defined at that point.

Now, the Domain consists of all x-values to the left of -1, Union all the x-values to the right of 1. This in interval notation is noted as:


\begin{gathered} (-\infty,-1)\cup(1,\infty) \\ \text{Domain}=\mleft\lbrace x\mright|x<-1\text{ or x>1}\} \end{gathered}

Then the Range is the set of all y-values reached by the x values of the domain, so in our case, this set consists of all y values larger than 2. which in set builder notation is written as:


\text{Range}=\mleft\lbrace y\mright|y>2\}

Pasting Image of Domain and Range below since user reports viewing problems:

it says I'm supposed to graph each function and then right down the domain and range-example-1
it says I'm supposed to graph each function and then right down the domain and range-example-2
User Ben Curthoys
by
2.7k points
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