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# Edexcel FP1 question watch

1. Hello, I wondered if someone could explain to me in detail how to do parts (e) and (f), with reasoning behind what to do? Many thanks!
2. (Original post by iMacJack)

Hello, I wondered if someone could explain to me in detail how to do parts (e) and (f), with reasoning behind what to do? Many thanks!
What is the x-coordiante of P. And how can you use that to find the y-coordinate?
3. (Original post by notnek)
What is the x-coordiante of P. And how can you use that to find the y-coordinate?
I don't know, hence I'm asking for help
4. (Original post by iMacJack)

Hello, I wondered if someone could explain to me in detail how to do parts (e) and (f), with reasoning behind what to do? Many thanks!
If you want a length, you'll want co-ordinates. And maybe a diagram if you haven't got one already. This should help for e and f . Think about the information given just before d.
5. (Original post by SeanFM)
If you want a length, you'll want co-ordinates. And maybe a diagram if you haven't got one already. This should help for e and f . Think about the information given just before d.
Part D I have, which is 9.
6. (Original post by iMacJack)
I don't know, hence I'm asking for help
Have you drawn a diagram?

Use the fact that P is 9 units from the directrix to find the distance from P to the x-axis.
7. (Original post by iMacJack)
Part D I have, which is 9.
It'll also help with part e and what I said, but as someone else is helping you I shall say no more.
8. (Original post by notnek)
Have you drawn a diagram?

Use the fact that P is 9 units from the directrix to find the distance from P to the x-axis.
Yes, I have a diagram and I know the x co-ordinate for P = 3, but I don't know why 9-6 is done.
9. (Original post by iMacJack)
Yes, I have a diagram and I know the x co-ordinate for P = 3, but I don't know why 9-6 is done.
If you know the x-coordinate of a point on a curve, you can use the equation of the curve to find the y-coordinate.

I don't know what you mean by the part in bold above.
10. (Original post by notnek)
If you know the x-coordinate of a point on a curve, you can use the equation of the curve to find the y-coordinate.

I don't know what you mean by the part in bold above.
So apparently to find the X value of P, you do 9 - 6, which gives x = 3 for P, but WHY is that done?
11. (Original post by iMacJack)
So apparently to find the X value of P, you do 9 - 6, which gives x = 3 for P, but WHY is that done?
The length of the x-axis to the directrix is 6 because its equation is x=-6.

The length of P to the directrix is 9.

The x-coordinate of P is the length of P to the x-axis.

With a diagram you should now be able to see it.
12. (Original post by notnek)
The length of the x-axis to the directrix is 6 because its equation is x=-6.

The length of P to the directrix is 9.

The x-coordinate of P is the length of P to the x-axis.

With a diagram you should now be able to see it.
I sort of see where you're coming from! Any chance you could walk me through the rest please!

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13. (Original post by iMacJack)
I sort of see where you're coming from! Any chance you could walk me through the rest please!

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By the rest do you mean part f or the end of part e?

For whichever part, please post where you're up to in the question and where you're stuck.
14. (Original post by notnek)
By the rest do you mean part f or the end of part e?

For whichever part, please post where you're up to in the question and where you're stuck.
I'm up to having the x co ordinate of 3 for P and the rest of part e please and part f if you'd be so kind

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15. (Original post by iMacJack)
I'm up to having the x co ordinate of 3 for P and the rest of part e please and part f if you'd be so kind

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I wrote the next step in an earlier post : if you have the x-coordinate of P, you can use the equation of the curve to find the y-coordinate.

And you can do a similar thing for point Q. Then the coordinates of P and Q are enough to find the distance PQ.

Once you've done part e, have another go at f and if you're still stuck, post your working and the point you got stuck.

We don't post solutions here so we can only help you if we know where you're up to.
16. (Original post by notnek)
I wrote the next step in an earlier post : if you have the x-coordinate of P, you can use the equation of the curve to find the y-coordinate.

And you can do a similar thing for point Q. Then the coordinates of P and Q are enough to find the distance PQ.

Once you've done part e, have another go at f and if you're still stuck, post your working and the point you got stuck.

We don't post solutions here so we can only help you if we know where you're up to.
Would I be right in assuming the q and p x co ordinates are the same

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17. (Original post by iMacJack)
Would I be right in assuming the q and p x co ordinates are the same

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Yes.
18. (Original post by notnek)
Yes.
Hi, are these the correct co ordinates

P = (3,sqrt62)
Q = (3, - sqrt 62)

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19. (Original post by iMacJack)
Hi, are these the correct co ordinates

P = (3,sqrt62)
Q = (3, - sqrt 62)

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It's not sqrt(62). Can you post your working showing how you got that?

It's possible you multiplied incorrectly. Try it again.
20. (Original post by notnek)
It's not sqrt(62). Can you post your working showing how you got that?

It's possible you multiplied incorrectly. Try it again.
Sorry yes I have multiplied incorrectly. Would it be sqrt 72 and -sqrt 72

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