You are Here: Home

# How to draw inequalities on a graph?

Maths and statistics discussion, revision, exam and homework help.

Announcements Posted on
1. How to draw inequalities on a graph?
Can someone explain how to draw these on a graph? And what they would look like?
Thanks.

2. Re: How to draw inequalities on a graph?
(Original post by blueray)
Can someone explain how to draw these on a graph? And what they would look like?
Thanks.

You draw the line , solid line if <= or >= and a dotted line if just < or >, then you shade the area you don't want, a quick way to check which area to shade is to choose a point on one side of the line and put the values into the inequality, if it comes out false you shade that side of the line, if true you shade the other side...
3. Re: How to draw inequalities on a graph?
(Original post by blueray)
Can someone explain how to draw these on a graph? And what they would look like?
Thanks.

Basically, change the inequality signs to equal signs and then you have your equations for lines.

Then you can either re-arrange them for y=... and plot the graph accordingly by subbing in x values.

Or the simpler and supposedly quicker route is to for all of these lines find the point where x is 0 and then the point where why is 0 and join them up to get your line. Do this for all the lines and you are sorted.
4. Re: How to draw inequalities on a graph?
(Original post by iCiaran)
You draw the line , solid line if <= or >= and a dotted line if just < or >, then you shade the area you don't want, a quick way to check which area to shade is to choose a point on one side of the line and put the values into the inequality, if it comes out false you shade that side of the line, if true you shade the other side...
You don't need to do dotted or solid lines. Look at the markscheme; they are all solid lines.
5. Re: How to draw inequalities on a graph?
(Original post by GreenLantern1)
You don't need to do dotted or solid lines. Look at the markscheme; they are all solid lines.

Only because they are all "or equal to"
6. Re: How to draw inequalities on a graph?
(Original post by iCiaran)
You draw the line , solid line if <= or >= and a dotted line if just < or >, then you shade the area you don't want, a quick way to check which area to shade is to choose a point on one side of the line and put the values into the inequality, if it comes out false you shade that side of the line, if true you shade the other side...

(Original post by GreenLantern1)
You don't need to do dotted or solid lines. Look at the markscheme; they are all solid lines.

(Original post by TenOfThem)
Only because they are all "or equal to"
Ok cheers guys, rearranged it and have got y= .....etc etc

Now I will plot them

But what was the rule? My teacher told me that it depends on certain factors. I forgot what they are ( did that in year 9) Can you explain them fully?

I have bolded that part above, can anyone verify it? Thanks.
7. Re: How to draw inequalities on a graph?
(Original post by blueray)

But what was the rule?

What rule

You just check any single point
8. Re: How to draw inequalities on a graph?
(Original post by TenOfThem)
Only because they are all "or equal to"
Mate I am doing this exam. I have also seen in other markschemes that where it is just > or < it has been produced with solid lines.
9. Re: How to draw inequalities on a graph?
(Original post by GreenLantern1)
Mate I am doing this exam. I have also seen in other markschemes that where it is just > or < it has been produced with solid lines.
Well considering the OP didn't mention which exam/exam board, it's quite impressive you know which one they are doing...

Dotted lines for < or > and solid for <= or >= is just convention, the mark scheme may allow only using solid lines, but using dotted is the "proper" way to do it.
10. Re: How to draw inequalities on a graph?
(Original post by GreenLantern1)
Mate I am doing this exam. I have also seen in other markschemes that where it is just > or < it has been produced with solid lines.
Well, mate, I do not know which syllabus the OP is following, nor which one you are following

I do know that there are exam boards that have dumbed down the requirements for mathematical accuracy because it seems that expecting students to follow conventions is too much .... and you may be correct that this is an example of that

However ... I think it is better to give explanations that include all the mathematically correct information whenever possible

11. Re: How to draw inequalities on a graph?
(Original post by iCiaran)
Well considering the OP didn't mention which exam/exam board, it's quite impressive you know which one they are doing...

Dotted lines for < or > and solid for <= or >= is just convention, the mark scheme may allow only using solid lines, but using dotted is the "proper" way to do it.

(Original post by TenOfThem)
Well, mate, I do not know which syllabus the OP is following, nor which one you are following

I do know that there are exam boards that have dumbed down the requirements for mathematical accuracy because it seems that expecting students to follow conventions is too much .... and you may be correct that this is an example of that

However ... I think it is better to give explanations that include all the mathematically correct information whenever possible

It is not actually impressive that I know which qualification and exam board the OP is doing, since we are both members of the Current Year 11 thread and he frequently PMs me questions about this Add Maths exam, of which he did to this link. Just saying.
12. Re: How to draw inequalities on a graph?
(Original post by TenOfThem)
Well, mate, I do not know which syllabus the OP is following, nor which one you are following

I do know that there are exam boards that have dumbed down the requirements for mathematical accuracy because it seems that expecting students to follow conventions is too much .... and you may be correct that this is an example of that

However ... I think it is better to give explanations that include all the mathematically correct information whenever possible

Fair enuf but this s for a specific exam so I feel it would make more sense for him to just do what is required for the exam.
13. Re: How to draw inequalities on a graph?
(Original post by GreenLantern1)
It is not actually impressive that I know which qualification and exam board the OP is doing, since we are both members of the Current Year 11 thread and he frequently PMs me questions about this Add Maths exam, of which he did to this link. Just saying.
I am not saying that you do not know ... just that I don't and would rather give correct information

Surely, even if your board does not require it now, it is better to know the conventions in car you go beyond your current level.

Just saying
14. Re: How to draw inequalities on a graph?
(Original post by GreenLantern1)
Fair enuf but this s for a specific exam so I feel it would make more sense for him to just do what is required for the exam.
As I said in post 13

Current exam is often a stepping stone rather than the finish line
15. Re: How to draw inequalities on a graph?
(Original post by TenOfThem)
As I said in post 13

Current exam is often a stepping stone rather than the finish line
True, but I was only letting him now that for this exam he din't need to do that.

Btw the other post as more directed to the other person when I was saying it wasn't impressive.
16. Re: How to draw inequalities on a graph?
(Original post by TenOfThem)
What rule

You just check any single point
then you shade the area you don't want, a quick way to check which area to shade is to choose a point on one side of the line and put the values into the inequality, if it comes out false you shade that side of the line, if true you shade the other side...

Is this correct? Does it always apply to everything.

(charlie, this is what I was talking about)

(Original post by GreenLantern1)
It is not actually impressive that I know which qualification and exam board the OP is doing, since we are both members of the Current Year 11 thread and he frequently PMs me questions about this Add Maths exam, of which he did to this link. Just saying.
We will both be doing the same exam, but Green they are right with the dotted thing, my maths teacher told me that as well.

Either way green is still great at maths
17. Re: How to draw inequalities on a graph?
(Original post by blueray)
then you shade the area you don't want, a quick way to check which area to shade is to choose a point on one side of the line and put the values into the inequality, if it comes out false you shade that side of the line, if true you shade the other side...

Is this correct? Does it always apply to everything.

Yes
18. Re: How to draw inequalities on a graph?
(Original post by GreenLantern1)
Mate I am doing this exam. I have also seen in other markschemes that where it is just > or < it has been produced with solid lines.
Which qualification/exam board are you taking?
19. Re: How to draw inequalities on a graph?
(Original post by TenOfThem)
Yes
The question says

shade the region which the region does not allow,

so I do that icirian says.

But if the question said

shade the region which the region does allow

then what would I do?
20. Re: How to draw inequalities on a graph?
(Original post by blueray)
The question says

shade the region which the region does not allow,

so I do that icirian says.

But if the question said

shade the region which the region does allow

then what would I do?
Well there are two regions so you would just shade in the other region (for each inequality).

I doubt that an exam question would ask you to shade in the "wanted" region.
Last edited by notnek; 06-05-2012 at 17:02.

## Step 2: Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank

this is what you'll be called on TSR

2. this can't be left blank

never shared and never spammed

3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
1. By completing the slider below you agree to The Student Room's terms & conditions and site rules

2. Slide the button to the right to create your account

You don't slide that way? No problem.

Last updated: May 6, 2012
Study resources