The Student Room Group

Will the real TeeEm please stand up!

Scroll to see replies

Original post by TeeEm
I hope I am correct ... I will attempt to write a neat solution for the easier one

I wish I could tell you if you were! Perhaps physicsmaths has been spending all day on it and is busy writing a similar solution :smile:
Original post by fatart123
I wish I could tell you if you were! Perhaps physicsmaths has been spending all day on it and is busy writing a similar solution :smile:


I havent tried it yet, tbh i dont want to as it looks horrendous.


Posted from TSR Mobile
Reply 1282
Original post by physicsmaths
I havent tried it yet, tbh i dont want to as it looks horrendous.


Posted from TSR Mobile


you do not have to ...

I think this is above the standard of Y13 including AEA/STEP
Original post by TeeEm
you do not have to ...

I think this is above the standard of Y13 including AEA/STEP


I think so.
But if i do try it i will go down the disc method if possible....


Posted from TSR Mobile
Reply 1284
Original post by physicsmaths
I think so.
But if i do try it i will go down the disc method if possible....


Posted from TSR Mobile


I will be grateful if you try to follow my method at some point to see if you can find any errors as it is 4 pages so it is very easy to make mistakes in such a lengthy piece of work
Original post by TeeEm
I will be grateful if you try to follow my method at some point to see if you can find any errors as it is 4 pages so it is very easy to make mistakes in such a lengthy piece of work


No problem, where is it?

Dw, found it.
Posted from TSR Mobile
Original post by TeeEm
I did not realise there were meant for me...
Clearly you are new here so you had not quoted me (like you just did) so there was no indication you were addressing me.

Anyway, what are these questions all about?



Not that important, I was just wondering about the quality of the questions, like in terms of difficulty and what not.
Original post by fatart123


Are those off some old FP1 paper? (Well, perhaps not all of them)


They aren't.
Reply 1288
Original post by PeakBellCurve II
Not that important, I was just wondering about the quality of the questions, like in terms of difficulty and what not.


Harder than the usual exam standards these days.
These are definitely questions you used to get in standard exams 25-30 years ago.
They are definitely good for practice
Reply 1289
Here are my workings for the easier question too

Determine the volume produced when the finite region bounded by y = x2 and y = x is revolved by a full turn about the line y = x
Original post by TeeEm
Here are my workings for the easier question too

Determine the volume produced when the finite region bounded by y = x2 and y = x is revolved by a full turn about the line y = x



Without knowing that formula beforehand, it's still pretty damn difficult to derive everything like that tbh

Original post by PeakBellCurve II
They aren't.



Oh, sure I've seen the log one before in an old FP1 textbook...

Original post by TeeEm
Harder than the usual exam standards these days.
These are definitely questions you used to get in standard exams 25-30 years ago.
They are definitely good for practice


The later questions in AQA fp papers are kinda like that. Edexcel is just way too easy
Reply 1291
Original post by fatart123
Without knowing that formula beforehand, it's still pretty damn difficult to derive everything like that tbh


It is very hard.

I had everything done correctly except the thickness for the element which is the smallest part in the calculation.

There is no formula as such.
In higher level calculus you have to derive the element and sum.

I am grateful for your research because I had spend ages on it and could not find the error
Original post by TeeEm
Here are my workings for the easier question too

Determine the volume produced when the finite region bounded by y = x2 and y = x is revolved by a full turn about the line y = x

In fact after seeing your solutions, I think this one may still be too difficult simply because the method is very unfamiliar - the only reason I would be able to attempt this Q is because you have given me questions on vol of rev ages ago where you work out 1 element then 'sum'. It's not necessarily difficult, just maybe a bit too left field for an A Level student.
Reply 1293
Original post by Gilo98
In fact after seeing your solutions, I think this one may still be too difficult simply because the method is very unfamiliar - the only reason I would be able to attempt this Q is because you have given me questions on vol of rev ages ago where you work out 1 element then 'sum'. It's not necessarily difficult, just maybe a bit too left field for an A Level student.


the question is too hard not for this but for it is very difficult to derive the "element".

Integrations as summations from first principles are part of M3 and M5 (examined)
and examinable in all advanced papers such as AEA or STEP.
Original post by TeeEm
the question is too hard not for this but for it is very difficult to derive the "element".

Integrations as summations from first principles are part of M3 and M5 (examined)
and examinable in all advanced papers such as AEA or STEP.


Haven't come across it yet then. What context does it come under in mechanics out of interest?
Original post by Gilo98
Haven't come across it yet then. What context does it come under in mechanics out of interest?


Centres of mass (m3) and moments of inertia (m5)
(edited 8 years ago)
Original post by Gilo98
In fact after seeing your solutions, I think this one may still be too difficult simply because the method is very unfamiliar - the only reason I would be able to attempt this Q is because you have given me questions on vol of rev ages ago where you work out 1 element then 'sum'. It's not necessarily difficult, just maybe a bit too left field for an A Level student.


The M3 first principles stuff isn't very hard and if the question was limited rotation about either the x or y axis, it would be very easy (the difficulty coming from the resulting integral). What makes it horrible is just the fact that it's about a slant line, and the steps to deriving the formula that TeeEm used being pretty abstract, at least to me.
Reply 1297
Original post by Gilo98
Haven't come across it yet then. What context does it come under in mechanics out of interest?


centre of mass in M3, and moment of inertia in M5
Reply 1298
Original post by fatart123
The M3 first principles stuff isn't very hard and if the question was limited rotation about either the x or y axis, it would be very easy (the difficulty coming from the resulting integral). What makes it horrible is just the fact that it's about a slant line, and the steps to deriving the formula that TeeEm used being pretty abstract, at least to me.


what about if I said to you rotate y = sinx 0 to pi about the y axis to find volume?
Have you seen that?
Original post by TeeEm
what about if I said to you rotate y = sinx 0 to pi about the y axis to find volume?
Have you seen that?


It's not in the Edexcel spec, but I think that I can remember the formula (opposite of x axis). Integrating arcsin^2(y) might be a bit difficult, can't really remember too much from FP3.

Quick Reply