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Will the real TeeEm please stand up!

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Original post by TeeEm
one question I made and added earlier


I shall have a go tomorrow, thanks for your help! PRSOM
Original post by TeeEm
one question I made and added earlier


Quick question. How come the sides of he rectangle are 4a and a respectively? Surely you can only relate them like this if this information is given in the question?
Reply 1562
Original post by Gilo98
Quick question. How come the sides of he rectangle are 4a and a respectively? Surely you can only relate them like this if this information is given in the question?


clearly ! did this in a hurry and forgot to add this bit of information in the text.

sorry
Original post by TeeEm
clearly ! did this in a hurry and forgot to add this bit of information in the text.

sorry


No worries I presumed that was the case. The method you used was what was important to me anyway.
Reply 1566
disgusting differential equation ...
any takers

(I planning to put this question as the last question in the IYGB Special Paper S)
Reply 1567
UPDATE ON I.Y.G.B SPECIAL PAPERS

So far uploaded in my site

Paper Z (final draft)
Paper Z (solutions)

Paper Y (final draft)
Paper Y (solutions)

Paper X (final draft)
Paper X (solutions)

Paper W (final draft)
Paper W (solutions)

Paper V (final draft)
Paper V (solutions)

Paper U (final draft)
Paper U (solutions)

Paper T (final draft)
Paper T (solutions)

Paper S (final draft)
Paper S (solutions)

Paper R (first draft)

NOTE that the solution files will be withdrawn after a short period of time as some teachers asked me to.

also look at
http://www.thestudentroom.co.uk/showthread.php?t=3595397
Reply 1568
To the people asking I can assure my site now is up to date.
Reply 1569
possibly undergrad
determine the value of a, a>0, for which the integral gives zero

Presentation1.jpg

any takers?
(edited 8 years ago)
Reply 1570
Any good method for this?
(please attach I do not have home-works any more!!!)

I have the correct answer (which is part of an undergrad question to which I am writing a solution)
It is just that the method seems a bit too long and I do not want to rewrite the solution as this integral lies somewhere in the middle of a longish problem

Thanks
(edited 8 years ago)
Original post by TeeEm
Any good method for this?
(please attach I do not have home-works any more!!!)

I have the correct answer (which is part of an undergrad question to which I am writing a solution)
It is just that the method seems a bit to long and I do not want to rewrite the solution as this integral lies somewhere in the middle of a longish problem

Thanks


Can it be done using A level methods? Im thinking hyperbolic.


Posted from TSR Mobile
Original post by TeeEm
Any good method for this?
(please attach I do not have home-works any more!!!)

I have the correct answer (which is part of an undergrad question to which I am writing a solution)
It is just that the method seems a bit to long and I do not want to rewrite the solution as this integral lies somewhere in the middle of a longish problem

Thanks


What is the answer? I did...something, but it's weird
Reply 1573
Original post by physicsmaths
Can it be done using A level methods? Im thinking hyperbolic.


Posted from TSR Mobile


All standard A level techniques except the infinity limit
Reply 1574
Original post by 1 8 13 20 42
What is the answer? I did...something, but it's weird


it is a mess to type

take the limit of the answer as k tends to zero

you should get 2pi
Original post by TeeEm
it is a mess to type

take the limit of the answer as k tends to zero

you should get 2pi


Got pi first but just forgot to account for chain rule on the arctan
Separating into two logs and then using IBP on both is fairly quick no? I guess It's not very pretty. And it's assuming the derivative of arctan is expected knowledge
(edited 8 years ago)
Reply 1576
Original post by 1 8 13 20 42
Got pi first but just forgot to account for chain rule on the arctan
Separating into two logs and then using IVP on both is fairly quick no? I guess It's not very pretty. And it's assuming the derivative of arctan is expected knowledge


I will try
I missed direct integration by parts
I did a substitution then parts which makes it longer.

My brain is totally fried

thanks
(edited 8 years ago)
I've got some cool integral questions somewhere, I hope @TeeEm won't mind if I post one or two here occasionally?

Here's some of the easiest: :colone:

tanx dx\int \sqrt{tan x}\ dx

arctan(x) dx\int arctan( \sqrt{x} )\ dx

Got lots of integral questions, not sure where they're from, but I printed them off in Year 12, and I don't recognise any of them from STEP :wink:
(edited 8 years ago)
Reply 1578
Original post by Johann von Gauss
I've got some cool integral questions somewhere, I hope @TeeEm won't mind if I post one or two here occasionally?

Here's some of the easiest: :colone:

tanx dx\int \sqrt{tan x}\ dx

arctan(x) dx\int arctan( \sqrt{x} )\ dx


No problem

the first one is famous

the second not sure .... is it hard without limits?
Original post by TeeEm
No problem

the first one is famous

the second not sure .... is it hard without limits?


First one is probably a classic, second one is very easy

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