# Thread: Piecewise function help check

1. ## Piecewise function help check

The picture of the graph is attached did I do this right?

Write the equation form of the piecewise function (all three) from left to right

Line 1 (left) I got -1/2x-4 for -4<x<-1
Line 2 (middle) 1x-1 for -1<x<2
Line 3 (right) y=2 for 2<x

Then we are to Find the domain and range I got

D: [-4,2] U [2,infinity) R: [-2,4]

2. Originally Posted by rj2001
The picture of the graph is attached did I do this right?

Write the equation form of the piecewise function (all three) from left to right

Line 1 (left) I got -1/2x-4 for -4<x<-1
Line 2 (middle) 1x-1 for -1<x<2
Line 3 (right) y=2 for 2<x

Then we are to Find the domain and range I got

D: [-4,2] U [2,infinity) R: [-2,4]
line 1 is incorrect

and note that your domain is equal to $\displaystyle [-4, \infty)$

and your last line is for $\displaystyle x \ge 2$

3. Yep agreed, line 1 is incorrect. Rise over Run, Rise is 2 Run is -1
$\displaystyle 2/-1=2$ so -2x on the interval you had, and line 3, just write it like Jhevon has it.

4. so now it says I have to find the function values f(-4) f(2) f(4) and f(100)

Do I just plug the #s to the x? which x? of the first line or second line? am I suppose to get multiple answers or should I have the same

5. Originally Posted by rj2001
so now it says I have to find the function values f(-4) f(2) f(4) and f(100)

Do I just plug the #s to the x? which x? of the first line or second line? am I suppose to get multiple answers or should I have the same
plug in the x's in their required piece-wise domain. example, to find f(-4) you would plug in -4 into line 1, why? because -4 is in the range $\displaystyle -4 \le x \le -1$. and so on