MedVision ad

Graphs question (1 Viewer)

hardworker42

New Member
Joined
Jan 27, 2014
Messages
3
Location
Sydney
Gender
Female
HSC
2014
I need some help, how do you get the domain and range of this graph
lyl = lx+1l
 

Cleavage

Clarence
Joined
Sep 1, 2013
Messages
563
Gender
Male
HSC
2014
Uni Grad
2018
I'm not sure, but if you were to plot the function y = |x+1|, then reflect it along the x axis, you should find the domain is all real x and range all real y
 

anomalousdecay

Premium Member
Joined
Jan 26, 2013
Messages
5,766
Gender
Male
HSC
2013
I'm not sure, but if you were to plot the function y = |x+1|, then reflect it along the x axis, you should find the domain is all real x and range all real y
Correct. Do a quick sketch for these questions to make sure that you get the correct domain and range.
 

braintic

Well-Known Member
Joined
Jan 20, 2011
Messages
2,137
Gender
Undisclosed
HSC
N/A
There is no need for a sketch to work out the domain and range.

Since |y| = a number which can't be -ve, all values of y are allowed.

Since | x+1 | = a number which can't be -ve, all values of x+1 are allowed and hence all values of x.
 

Cleavage

Clarence
Joined
Sep 1, 2013
Messages
563
Gender
Male
HSC
2014
Uni Grad
2018
There is no need for a sketch to work out the domain and range.

Since |y| = a number which can't be -ve, all values of y are allowed.

Since | x+1 | = a number which can't be -ve, all values of x+1 are allowed and hence all values of x.
I get what you mean, this question doesn't require any work, mostly intuitive thinking. But its good to get into the habit of finding the domain and range through working, and drawing the graph is a good way of doing this.d
 

anomalousdecay

Premium Member
Joined
Jan 26, 2013
Messages
5,766
Gender
Male
HSC
2013
I get what you mean, this question doesn't require any work, mostly intuitive thinking. But its good to get into the habit of finding the domain and range through working, and drawing the graph is a good way of doing this.d
If you want to minimise silly mistakes in the exam, you have to get into that habit.

Of course there is no need to sketch but a quick 5 second check will assure your answer.

Also, OP did not know how to find it, so the best thing is for them to learn by sketching to start off, then when they get better they will understand (we just take the short-cut of sketching it in our head and imagining it because we started off by learning to sketch to help us out when we started learning this).
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top