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# Decision 1 matchings help! watch

1. I'm really stuck on part b, I just can't see how to match everything up... does complete matching mean I have to match all the letters with the numbers i.e. no unmatched vertices? I keep having one vertice unmatched on the left and right hand side... Would really appreciate some help, thanks
2. Can anyone help me?
3. (Original post by jordanwu)
Can anyone help me?
SeanFM
4. (Original post by jordanwu)

I'm really stuck on part b, I just can't see how to match everything up... does complete matching mean I have to match all the letters with the numbers i.e. no unmatched vertices? I keep having one vertice unmatched on the left and right hand side... Would really appreciate some help, thanks
Yes, complete matching means that everything is matched up to no more than 1 node.

If you start off with the matching they give, and then go down the alphabet side, you'll see that A is matched and B is matched, so the first one that isn't is C, and this one has a fairly easy matching. Then you should be able to properly apply it to the remaining one.
5. (Original post by SeanFM)
Yes, complete matching means that everything is matched up to no more than 1 node.

If you start off with the matching they give, and then go down the alphabet side, you'll see that A is matched and B is matched, so the first one that isn't is C, and this one has a fairly easy matching. Then you should be able to properly apply it to the remaining one.
What I don't get is how to write down the answer, I'm just not sure if I've done it wrong, but this is what I came up with:

C-4+B-3+A-1+E-5

But then D on the left and 2 on the right aren't matched.. I'm not sure what to do next :/
6. (Original post by jordanwu)
What I don't get is how to write down the answer, I'm just not sure if I've done it wrong, but this is what I came up with:

C-4+B-3+A-1+E-5

But then D on the left and 2 on the right aren't matched.. I'm not sure what to do next :/
You can always apply the algorithm twice. Matching C to 2 straight away would have been easier though.

I'm not sure what exam board you're with it how they want you to answer these questions.

For Edexcel:

C-4=B-3=A-1=E-5 where - means 'could be matched to' and = means 'is currently matched to.

You them write 'change status' and swap the - for = and = for -, so it becomes

C=4-B=3-A=1-E=5.

If + is the same as = then you should be fine.
7. (Original post by SeanFM)
You can always apply the algorithm twice. Matching C to 2 straight away would have been easier though.

I'm not sure what exam board you're with it how they want you to answer these questions.

For Edexcel:

C-4=B-3=A-1=E-5 where - means 'could be matched to' and = means 'is currently matched to.

You them write 'change status' and swap the - for = and = for -, so it becomes

C=4-B=3-A=1-E=5.

If + is the same as = then you should be fine.
I'm with AQA, and yh I think + means the same thing as =.
If I decided to match D with 4:
D-4+B-3+A-1+E-5, but then what would I write down for C to be matched with 2? Just C-2??
Then the complete matching would be: A-1, B-3, C-2, D-4, E-5??
8. (Original post by jordanwu)
I'm with AQA, and yh I think + means the same thing as =.
If I decided to match D with 4:
D-4+B-3+A-1+E-5, but then what would I write down for C to be matched with 2? Just C-2??
Then the complete matching would be: A-1, B-3, C-2, D-4, E-5??
Just C-2 yes, I'm not sure if for AQA you need to show the change by writing C+2 underneath it.

Otherwise that should be correct.
9. (Original post by SeanFM)
Just C-2 yes, I'm not sure if for AQA you need to show the change by writing C+2 underneath it.

Otherwise that should be correct.
OK thanks I'll check with my teacher just to make sure

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