Stuck on a Conic

Original post by TeeEm

correct now
:smile:

Aw yiss. Is 2a = 5?

Reply 21

OP

Original post by Zacken

Aw yiss. Is 2a = 5?

it is

Reply 22

Original post by TeeEm

it is

I made a simple error at the end, I said 2*5/2 = 2....... :frown:

Reply 23

OP

Original post by Zacken

I made a simple error at the end, I said 2*5/2 = 2....... :frown:

I will post my solutions (the polar version is interesting )
one of the things maths lacks this days is you cannot get a question such as this as polars and conics are in different modules

Reply 24

Original post by TeeEm

I will post my solutions (the polar version is interesting )
one of the things maths lacks this days is you cannot get a question such as this as polars and conics are in different modules

You can! Like, for example - there are no pulleys in M2, but this year, my paper had pulleys because it was still in M1! Tag me when you put the polar version up, I'd be interested in having a look at it! :smile:

Reply 25

OP

Original post by Zacken

You can! Like, for example - there are no pulleys in M2, but this year, my paper had pulleys because it was still in M1! Tag me when you put the polar version up, I'd be interested in having a look at it! :smile:

...

I see I am too late, anyways...

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Reply 27

OP

Original post by DylanJ42

I see I am too late, anyways...

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Friday night you see ... I am going to a party ...

Reply 28

16Characters....

13

Conics are on my list of things to do this half-term break, *bookmarks*

Reply 29

DylanJ42

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Original post by TeeEm

Friday night you see ... I am going to a party ...

There is no party like a maths forum party :cake:

Reply 30

theOldBean

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Original post by TeeEm

could you point me in the right direction?

I think I might be missing a joke here but the property you are asking for (i.e. sum of the distances from the foci is constant) is true for all ellipses, not just the particular one given in the question.

(So the easiest way to do the question is to simply quote that theorem :P)

Reply 31

Original post by TeeEm

...

Sweet, thanks! :biggrin:

Reply 32

Original post by theOldBean

I think I might be missing a joke here but the property you are asking for (i.e. sum of the distances from the foci is constant) is true for all ellipses, not just the particular one given in the question.

It is, but that doesn't mean you can't prove it for a specific special, can you?

Reply 33

OP

Original post by theOldBean

I think I might be missing a joke here but the property you are asking for (i.e. sum of the distances from the foci is constant) is true for all ellipses, not just the particular one given in the question.

(So the easiest way to do the question is to simply quote that theorem :P)

Sorry but I make the question and I do not expect the student not to use any well known theorems ...
If I was to put this in an exam i would state it clearly.

All the best !

Reply 34

B_9710

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Attachment not found

Bit late.
I have no idea why all 3 of these pictures are displayed sideways. I took them from my phone the correct way up.

Original post by theOldBean

I think I might be missing a joke here but the property you are asking for (i.e. sum of the distances from the foci is constant) is true for all ellipses, not just the particular one given in the question.

(So the easiest way to do the question is to simply quote that theorem :P)

That's what I thought, sum of distance from two foci is = 2 x semi major axis. But I guess in this question you are proving it for a special case.

Reply 36

Louisb19

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Original post by TeeEm

could you point me in the right direction?

I didn't know that ellipses had such elegant polar equations.

Reply 37

OP