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Mathematics 20 Online
OpenStudy (anonymous):

5-8 Graphing absolute value functions. 36. Y = |x| + 2 37. Y= |x| -7 38. Y = |x + 3| 39. Y = |x – 5| Write an equation for each translation of y = |x| 40. 5.5 units down. 41. 11 units left 42. 13 units up 43. 6.5 units right 44. Write an equation for the absolute value function at the right. PLEASE HELP.

OpenStudy (solomonzelman):

Rules of \(\large\color{black}{ \rm shifts }\) from \(\large\color{black}{ \rm f(x) }\) to \(\large\color{black}{ \rm g(x) }\). \(\large\color{black}{ \rm f(x)=a\left| x \right| ~~~~~~~~~\rm{\Longrightarrow}~~~~~~~~\rm g(x)=a\left| x \color{blue}{ -~\rm{c} }\right| }\) \(\large\color{blue}{ ~\rm {c} }\) units to the \(\normalsize\color{blue}{ \rm right }\). \(\large\color{black}{ \rm f(x)=a\left| x \right| ~~~~~~~~~\rm{\Longrightarrow}~~~~~~~~\rm g(x)=a\left| x \color{blue}{ +~\rm{c} }\right| }\) \(\large\color{blue}{ ~\rm {c} }\) units to the \(\normalsize\color{blue}{ \rm left }\). \(\large\color{black}{ \rm f(x)=a\left| x \right| ~~~~~~~~~\rm{\Longrightarrow}~~~~~~~~\rm g(x)=a\left| x \right| \color{blue}{ +~\rm{c} }}\) \(\large\color{blue}{ ~\rm {c} }\) units \(\normalsize\color{blue}{ \rm up }\). \(\large\color{black}{ \rm f(x)=a\left| x \right| ~~~~~~~~~\rm{\Longrightarrow}~~~~~~~~\rm g(x)=a\left| x \right| \color{blue}{ -~\rm{c} }}\) \(\large\color{blue}{ ~\rm{c} }\) units \(\normalsize\color{blue}{ \rm down }\). Also, the ` reflection across the X -axis. ` \(\large\color{red}{ \rm f(x)=\left| x \right| ~~~~~~~~~\rm{\Longrightarrow}~~~~~~~~\rm g(x)=\color{blue}{ - }\left| x \right| }\) (the \(\large\color{red}{ ~\rm{f(x)} }\) and \(\normalsize\color{red}{ \rm g(x) }\) are mirrors of each other over the \(\large\color{red}{ \rm{x-axis} }\). ) \(\LARGE\color{white}{ \rm │ }\) And lastly, \(\normalsize\color{black}{ \rm{ s~t~r~e~t~c~h~i~n~g} }\) \(\large\color{black}{ \rm f(x)=\left| x \right| ~~~~~~~~~\rm{\Longrightarrow}~~~~~~~~\rm g(x)=\color{blue}{ c }\left| x \right| }\) For any real number \(\normalsize\color{blue}{ \rm{c} }\), (provided that \(\normalsize\color{blue}{ \rm{c\neq1~~or~~0} }\) ) \(\normalsize\color{black}{ \rm{1)} }\) When \(\normalsize\color{blue}{ \rm{\left| c \right| >1} }\) the (new function) \(\normalsize\color{black}{ \rm{g(x)} }\) is streched \(\normalsize\color{blue}{ \rm{ vertically} }\). (if comparing to the initial function \(\normalsize\color{black}{ \rm{f(x)} }\). ) \(\normalsize\color{black}{ \rm{2)} }\) When \(\normalsize\color{blue}{ \rm{\left| c \right| <1} }\) the (new function) \(\normalsize\color{black}{ \rm{g(x)} }\) is streched \(\normalsize\color{blue}{ \rm{ horizontally} }\). (if comparing to the initial function \(\normalsize\color{black}{ \rm{f(x)} }\). )

OpenStudy (solomonzelman):

do you see weird codes or normal text?

OpenStudy (anonymous):

Normal text.

OpenStudy (solomonzelman):

the codes aren't working for me for some reason, so it loks like a fine set of rules, correct?

OpenStudy (solomonzelman):

if you have some questions still, then ask away.

OpenStudy (anonymous):

Yes it does.

OpenStudy (solomonzelman):

the codes aren't working for me for some reason, so it loks like a fine set of rules, correct?

OpenStudy (solomonzelman):

if you have some questions still, then ask away.

OpenStudy (anonymous):

Still kind of confused about this, just so new to this subject.

OpenStudy (solomonzelman):

you can see that you are adding +2 (in the first problem) right? If you know what a graph of \(\large\color{black}{ y=\left| x \right| }\) is like, then shift it accoring to the rules I posted.

OpenStudy (anonymous):

so number 1 will be -2?

OpenStudy (solomonzelman):

no not minus 2, although you are getting the 2 correctly. going from, \(\large\color{black}{ y= \left| x \right| }\), the function, \(\large\color{black}{ y=\left| x \right| \color{blue}{+2} }\) is shifted up, correct?

OpenStudy (anonymous):

I guess.

OpenStudy (solomonzelman):

looking at the third rule, your "a" is just 1, so we can re-write it as: \(\large\color{black}{ \rm f(x)=\left| x \right| ~~~~~~~~~\rm{\Longrightarrow}~~~~~~~~\rm g(x)=\left| x \right| \color{blue}{ +~\rm{c} }}\) \(\large\color{blue}{ ~\rm {c} }\) units \(\normalsize\color{blue}{ \rm up }\). you see that your "+2", is the "+c" here?

OpenStudy (anonymous):

Yes I see that.

OpenStudy (anonymous):

would my answer be g (x) = x + 2

OpenStudy (solomonzelman):

you mean, \(\large\color{black}{ y= \left| x \right| +2 }\) ? and don't you have to graph it though? are you allowed to use a graphing calculator or not?

OpenStudy (anonymous):

Yes I am, and yeah i mean that just didn't punch the letters in. and i'm not really sure, its a chapter review on an online school..

OpenStudy (solomonzelman):

okay, lets start from graphing the parent function, \(\large\color{black}{ y= \left| x \right| }\), do you know how to do this, or want me to help you doing this?

OpenStudy (anonymous):

Need help. I mostly learn from a teacher, kinda hard with online school not having that extra help. please

OpenStudy (solomonzelman):

okay, lets plug in some values. you will need to tell me the following: \(\large\color{black}{ \bullet }\) \(\large\color{black}{ \left| ~-1 ~\right| =? }\) \(\large\color{black}{ \bullet }\) \(\large\color{black}{ \left| ~1 ~\right| =? }\) \(\large\color{black}{ \bullet }\) \(\large\color{black}{ \left| ~-2 ~\right| =? }\) \(\large\color{black}{ \bullet }\) \(\large\color{black}{ \left| ~2 ~\right| =? }\) tell me all of the four, what they are equal to, receptively please.

OpenStudy (solomonzelman):

you know what \(\large\color{black}{ \left| ~-1 ~\right| }\) is equal to, right?

OpenStudy (anonymous):

Is it -1?

OpenStudy (solomonzelman):

no, the absolute value is always positive. because absolute value is basically the distance. the distance from 0 to -1, is the same as the distance from 0 to 1. Correct? So \(\large\color{black}{ \left| ~-1 ~\right| =1 }\) (just like for any positive number \(\large\color{black}{ c }\), \(\large\color{black}{ \left| ~-c~\right| =c }\) )

OpenStudy (solomonzelman):

So you can say that: \(\large\color{black}{ \left| ~\pm1 ~\right| =1 }\) (saying that \(\large\color{black}{ \left| ~-1 ~\right| }\) and \(\large\color{black}{ \left| 1 ~\right| }\) are both equal to \(\large\color{black}{ 1 }\) )

OpenStudy (anonymous):

Oh okay! so 1=1,- 2=2?

OpenStudy (anonymous):

Yeah

OpenStudy (solomonzelman):

so can you tell me what \(\large\color{black}{ \left| ~-3 ~\right| }\) will be?

OpenStudy (anonymous):

3.

OpenStudy (solomonzelman):

Yes that is correct

OpenStudy (solomonzelman):

So we can say the following statements: (I'll use a blue color) \(\large\color{blue}{ \left| ~\pm1 ~\right| =1 }\) \(\large\color{blue}{ \left| ~\pm2 ~\right| =2 }\) \(\large\color{blue}{ \left| ~\pm3~\right| =3 }\) \(\large\color{blue}{ \left| ~\pm4 ~\right| =4 }\) yes?

OpenStudy (solomonzelman):

and on...

OpenStudy (anonymous):

Yep.

OpenStudy (solomonzelman):

so when we have: \(\large\color{blue}{ y=\left| x~\right| }\) let's plug in values: when \(\large\color{blue}{ x=-1 }\), then \(\large\color{blue}{ y=1 }\). when \(\large\color{blue}{ x=1 }\), then \(\large\color{blue}{ y=1 }\). when \(\large\color{blue}{ x=-2 }\), then \(\large\color{blue}{ y=2 }\). when \(\large\color{blue}{ x=2 }\), then \(\large\color{blue}{ y=2 }\).

OpenStudy (anonymous):

so for number one would it be x=5.5 y = 5.5?

OpenStudy (anonymous):

I mean number 40- oops

OpenStudy (solomonzelman):

no, for your problem 36 the graph is shifted from the parent function, so let first graph the parent, and then see what happens when we shift it.

OpenStudy (anonymous):

Okay.

OpenStudy (solomonzelman):

|dw:1418938917989:dw|

OpenStudy (solomonzelman):

https://www.desmos.com/calculator/xy3lqozckt this si the graph of the parent function, \(\large\color{blue}{ y=\left| x \right| }\)

OpenStudy (anonymous):

|dw:1418939054181:dw| is this right?

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