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Posted by: DeepRoots Sep 19 2007, 04:21 AM

Anyone out there enjoy a good number crunch? I'm doing A-level maths and am staring blankly at a piece of paper holding a set of questions i just can't do.

just to see how many of you like / can do maths i'll throw one out and see how it goes....

(maybe your proof will help me understand)

Show that the equation of the tangent to the curve
y=7x^2 - 2e^x at the point where x=2 is
y=(28 - 2e^2)x + 2e^2 - 28.

Cheers for your help....if you can handle it ( evil laugh fading out......)

Posted by: Ayen Sep 19 2007, 04:44 AM

The answer is 42.

Hope you get the reference

I'd honestly love to help but that looks like someone fell on a keyboard a few times .

Posted by: blindwillie Sep 19 2007, 04:45 AM

I dnt get the bends really. Can you tab it for me?

Posted by: DeepRoots Sep 19 2007, 04:50 AM

i guess you guys see this and think the same as i do- "screw this i'm grabbing my guitar".

At this point in the course thats a bad thing for me to be thinking.....

@ Ayen : yeh i get the reference- and that thing hitting the keyboard was my head

@ blindwillie : this type of bend is often a problem for guitarists that arent nerds- just ask your nearest maths teacher for details on this issue

Posted by: blindwillie Sep 19 2007, 04:53 AM

Sorry for making a joke of it, just couldn't resist. I'm to no help. I've been through this but I found it boooring and tideous and that stuff didn't stick.

Posted by: DeepRoots Sep 19 2007, 04:54 AM

amen to that...

cheers anyway

Posted by: Fsgdjv Sep 19 2007, 05:19 AM

Don't you just derivate (if it's called that in english, I just made that up) it and put x = 2? And then it's done?

I'm sorry if I'm no help, because since you're doing A-level maths (I suppose on university level), the solution must be harder than that, but it looked so easy.. I don't know. Hope I helped, otherwise just ignore me:p

Posted by: Resurrection Sep 19 2007, 05:22 AM

I'll take a shot. First differentiate y with respect to x using your first equation. This results in dy/dx = 14x - 2e^x and represents the gradient (tangent) at any point. Since we're interested in x=2, plug this value into dy/dx to get a gradient of m = 28 - 2e^2. Since the equation of a straight line is y = mx + c, and we've just found m, we only now need to find the Y-axis intercept c. But we know we've got a straight line passing through the point x=2, y=28 - 2e^2 (from your first equation) AND it has a gradient of 28 - 2e^2. Therefore the line crosses the Y axis at -(28 - 2e^2) or equivalently 2e^2 - 28 and gives us the value of c. So, the equation of the tangent at x=2 is therefore y = (28 - e^2)x + 2e^2 - 28 which agrees with the second equation in your post.

Best of luck in your exam!

Posted by: mattacuk Sep 19 2007, 07:03 PM

Well Im impressed

Posted by: DeepRoots Sep 19 2007, 08:30 PM

wow. that was an awesome explanation. thanks alot ressurrection! much better than my teacher

i hope you dont mind me pestering you via PM for when i get stuck next time.

Great help

Posted by: Andrew Cockburn Sep 19 2007, 11:48 PM

No good deed ever goes unpunished ...

Posted by: DeepRoots Sep 19 2007, 11:54 PM

haha!

Posted by: botoxfox Sep 20 2007, 01:04 AM

.

Posted by: Pavel Sep 20 2007, 01:25 AM

Maths? You gotta be kidding!

I would be of better use in sweeps than in maths

Posted by: Iluha Sep 20 2007, 02:06 AM

If you asked me this 2 years ago I would have had an answear for you, but I forgot all my math now.

Posted by: FretDancer69 Sep 20 2007, 06:56 AM

yeah i hate it too!!!!!

Posted by: Resurrection Sep 23 2007, 07:02 PM

Glad to have been of help.

To all the other posters, how can you possibly hate mathematics?

Seriously though, most of it is getting to grips with terminology, technique and the proper frame of mind. Kinda like guitar playing

Posted by: botoxfox Sep 23 2007, 07:46 PM

I just find mathematics boring, I wish I didn't, but I just do. I kinda feel that numbers hate me. They just jump up from the paper like shrapnel into my face.

Posted by: mattacuk Sep 23 2007, 08:36 PM

Im probably as poor in mathematics as you can get Not because I don’t feel i have the intelligence, rather I wasn’t given the opportunity in school to learn as my class size was huge and teachers rarely turned up

Posted by: tonymiro Sep 23 2007, 08:53 PM

Rightly or wrongly if you want to study any science or science related subject post 16 then a good grounding in maths and/or stats is pretty much a prerequisite.

In the UK in the past you also needed a pass at what was then "O" level grade C (or CSE grade 1) in both English and Maths in addition to the required grades for subjects studies at 'A' level to enter University. My wife had to take her "o" level maths several times to get the pass mark so that she could go to uni despite v good grades in her 'a' levels . Have to say that even now it's me that helps our daughter with her maths homework lol: .

Cheers,
Tony

Posted by: fkalich Sep 23 2007, 09:26 PM

I personally respect kids who have an appreciation for such things.

This is the last math I took

http://en.wikipedia.org/wiki/Fourier_transform

Math gets weird. At a point it really starts to be like philosophy, it make you start seeing reality in a way you maybe did not see it before. It gets spooky.

edit:

I highly expect that Jimmy Page liked his math. In his legendary skiffle video, he says he wants to do biological research as a career. From the looks of it, I expect JP was the only one in that band not to be a PhD. And I expect he ended up the richest.

http://youtube.com/watch?v=cKUyHpoWnT4

Posted by: tonymiro Sep 23 2007, 10:37 PM

When I used to a research chemist I had to use a fair bit of instrumentation based on fft fkalich . Having an understanding of the maths really helped. I also found maths really good to understand the physics behind the sort of chemistry I was mainly involved in (chemical analysis based on mass spectroscopy - the math helped me understand both how molecules might statiscally favour one decay and how the unstable molecule could be stabilised - temporarily - in 3d space for analysis).

At this end I agree that the math quickly moves towards philosophy - I've some friends who did their PhDs in philosophy on issues to do with quantum maths, chaos theory and so on .

Cheers,
Tony

Posted by: Resurrection Sep 24 2007, 12:49 AM

I'm an engineer by trade, so the FFT and associated works of Mr Fourier have been part of my life for a long time too!! The strong links between mathematics, philosophy and related disciplines are rooted in history. A lot of mathematical principles were dreamt up to explain fundamental questions about the world. Until relatively recently, the best mathematical minds often belonged to people who worked in philosophy, astronomy and a whole bunch of other disciplines.

Kudos to fkalich. I'd forgotten about the Jimmy Page "biological research" video. Queen are the other band that spring to mind when it comes to higher-level education. I think most of the members were at university and Brian May was working on an astrophysics PhD (which he went back and completed only recently, or did I imagine that story?)

Posted by: tonymiro Sep 24 2007, 01:03 AM

Have a feeling that Andy Summers out of the Police has a PhD . Pat Kane (Hew and Cry) is a visiting Prof at York.

Seems unlikely that Brian May could have completed a (the same) PhD after a long lay off. A major criteria for a PhD is 'originality' and so you are under pressure to complete before anyone else does something too similar.
He might however have submitted a new thesis and I'm pretty certain that he has at least one honorary doctorate.

Cheers,
Tony

Posted by: Resurrection Sep 24 2007, 01:23 AM

According to Wikipedia, Brian May is due to receive his PhD in 2008, subject to thesis corrections. His most recent research does seem to be related to the original research he carried out (velocities in astronomical dust clouds ) but you could well be correct that the specific topic of his recent thesis was modified to ensure originality. He already holds honary doctorates from the universities of Hertfordshire and Exeter

Posted by: Zephyr Sep 24 2007, 01:30 AM

Hehe... Six times nine? Douglas Adams is my hero.

Posted by: Nick334 Sep 24 2007, 01:50 AM

I really hope that was a joke. 6x9?

Posted by: tonymiro Sep 24 2007, 03:29 AM

Just had a look At Brian May's official site and the blog mentions does his impending PhD, subject to corrections, Resurrection so a congrats to Brian is in order. Not easy to get; not least with all his other commitments.

(PhD trivia - UK PhD are subject to the following, using my University scale:

5.1 - Straight pass, no corrections, immediate designation of PhD/Dr of ...
5.2 - Pass with Minor Correction - subject to examiners approval may start to call oneself Dr. Corrections identified submitted within a specified time and subject to approval by lead examiner.
5.3 - Pass subject to Minor Corrections subject to approval - as above but cannot use Dr title until corrections approved.
5.4 Pass subject to Major Corrections - As 5.3 but major corrections are required.
5.5 - Redesignation subject to correction- Award of a 'lower' qualification - ie MPhil/MRes. No PhD.
5.6 - Fail

If a Thesis is submitted with supervisory approval then 5.6 should be rare. Most PhD candidates that are not likely to make the grade are generally councilled not to submit long before the date. Many PhD candidates drop out before completion/submission for lots of reasons. UK prefer submission, for a full time PhD, within a 3-5 year window: part time pro-rata. Most UK Universities also stipulate a minimum time period before you are allowed to submit.

In the UK you are orally examined by an internal and several external examiners on a written thesis that you submit. The thesis is usually between 40-80,000 words. Oral examination usually are between 1-4 hours but some go longer.

PhD is in most countries the highest educational examined award you can achieve. In many countries a professorship is an honorary title not an examined award. So Brian has shown both his tenacity and ability in astrophysics to achieve one. Kudos to Brian.)

Cheers,
Tony

Posted by: kevin-riff-after-riff Sep 24 2007, 04:53 AM

nooooo idea haha

Posted by: Resurrection Sep 24 2007, 10:03 PM

You really have to read The Hitch-hikers Guide to the Galaxy to appreciate the humour!

Posted by: Nick334 Sep 26 2007, 12:02 AM

I have read them but he said 6x9=42.

Posted by: Resurrection Sep 26 2007, 04:57 AM

In the Hitch-hikers books there is a scene when Ford and Arthur are trying to find the Question that corresponds to the Answer to Life, the Universe and Everything (the answer being the infamous 42). They think that the Question is buried deep in Arthurs brain since he is a native of Earth, which is actually a planet-sized supercomputer built to work out what the Question is. However, it turns out that modern humanity (including Arthur) is not descended from the original people living on Earth but from a race of human-like (and fairly stupid) aliens who crashed on Earth after it was made. Ford reckons that since Arthur grew up on Earth, but is not a true and original part of the Earths programming, he may know the Question in an incorrect or distorted form. In order to bring out this distorted version of the Question from his subconscious, Arthur draws random letters from a game of Scrabble. The letters spell out the following words.

"What do you get if you multiply six by nine?"

Earlier in the books, a theory had been put forward that the proper Question was "what do you get if you multiply six by seven?" but this had been rejected on the grounds that it was "too factual" and "wouldn't sustain the punters interest".

Posted by: tonymiro Sep 26 2007, 05:33 AM

Absolutely Resurrection,
part of the humour in Hitchhiker's was to unsettle and question what we take as a given fact about the Universe...

Cheers,
Tony