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D1 Linear programming rejecting area watch

1. Can someone talk me through how to reject the regions, I can't get to grips with how it explained in the book.

Example:

That is the first line I can reject the area since I can just tell by looking at the direction of the inequality.

The second line which is required to draw im not sure which area to reject.
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2. The easiest way is to ask yourself, "Does the point (1,1) lie in the region or not?". (My first choice of point would be (0,0), but that doesn't help us at all for this one, because it lies on the border.)
3. (Original post by Smaug123)
The easiest way is to ask yourself, "Does the point (1,1) lie in the region or not?". (My first choice of point would be (0,0), but that doesn't help us at all for this one, because it lies on the border.)

Looking at (1,1) how would I know if it lies in the region? using the inequalities 3(1) > 2(1) but how would I know what area to reject knowing 3 is greater than 2?
4. (Original post by franzk)

Looking at (1,1) how would I know if it lies in the region? using the inequalities 3(1) > 2(1) but how would I know what area to reject knowing 3 is greater than 2?
(1,1) lies above your yellow line; you have that (1,1) is in the region we want to keep if and only if 3 >= 2, and happily 3 is greater than 2, so (1,1) is in the region. That is, (1,1) is a point which satisfies the inequality, and so we keep it as well as everything that's in the same region as it, and reject the rest (that is, the other side of the line).
Once you've finished considering each inequality separately, you can then put them back together, removing every region that you rejected along the way.
5. Once you drew a line , you test a point (x,y) that is not on the line into the equation ,

say for 5x+4y > 80

test (0,0)

you can see that 0 is not > than 80 , which means (0,,0) is not True

Therefore you shade out anything BELOW THE LINE which you have done !
6. (Original post by franzk)
Can someone talk me through how to reject the regions, I can't get to grips with how it explained in the book.

Example:

That is the first line I can reject the area since I can just tell by looking at the direction of the inequality.

The second line which is required to draw im not sure which area to reject.
7. (Original post by charly2012)
Once you drew a line , you test a point (x,y) that is not on the line into the equation ,

say for 5x+4y > 80

test (0,0)

you can see that 0 is not > than 80 , which means (0,,0) is not True

Therefore you shade out anything BELOW THE LINE which you have done !
3(1) is greater than 2(1) so i should not shade under the line? - for the second equation

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