So I'm trying to figure out a matrix issue while studying 18.03 and, realizing I have very little idea how to do it, I let my eyes stray to the next problem. This may have been, subconsciously, due to the hope that I may understand the next question and not feel dumb. Unfortunately (fortunately?) before I got a chance to comprehend the next problem I saw the words "critical point." This reminded me of something.

While many are now completely done with their year at MIT, there are still hundreds of students that are knee-deep in finals (including yours truly). Finals at MIT are just like finals anywhere, tests that see if you remember everything from an entire semester. Like anywhere else, all of these tests are crammed into one week, and again, just like any other place, there isn't a lot of time to study between finals.

People describe an education at MIT like drinking out of a fire hose. That's because MIT shoves as much knowledge down your throat as possible in the shortest amount of time it can. An example? AB --> BC Calculus in high school is designed to take about a year and a half. At MIT the equivalent course is 18.01. It takes 3 months. If you're feeling really hardcore you can take 18.01A which shoves all of multivariable calculus in there as well, but graciously gives you an extra month. That's right, two and a half years of high school math condensed into 4 months. And then, at the end, a final.

This class is not a particularly cruel exception. Most classes at MIT operate at a very fast pace and leave the student feeling comfortable about a lot of different things at the end of the semester but not necessarily ready to solve any problem you throw at them. This is why finals at MIT are a whole new kind of special.

Many different acronyms have been invented for the word "finals," most of which are kind of crude and can readily be found on Facebook (I'll leave the legwork up to you) but all center around never having actually learned anything being tested. Realizing this the week of finals scares MIT students, causing them to frantically study and try to learn an entire MIT semester's worth of work in a day or two. The definition of "day" becomes very nebulous at this point as sweatpants and flip-flop-clad knowledge harvesting beavers roam from review session to review session, library to library (for the quiet more than for the books), completely unaware of the fact that it's 2 in the morning. Sleep schedules shift and get all wacky as life becomes more about learning than sleeping. Take a couple of examples:

Maddie '11, after staying up until 5ish studying for 2.001, gets about 3 hours of sleep, takes her final, and then falls asleep for 6 hours. She wakes up at 8, completely rested and effectively has just reversed her internal clock, ready to go just as the sun sets (luckily this had a happy ending, she was able to get back to sleep later and woke up at a normal hour, well rested and un-jet-lagged).

Michelle '11 decided just not to sleep before her 7.013 final, going at it after having been awake for over 24 hours. Her nap afterwards did the same thing as Maddie's, taking her right into evening and nocturnalizing her. The same thing happened to Jon '11.

So, "critical point," how does that fit in? It seems like every night for the last three nights, whenever I'm not studying I'm in some kitchen or lounge listening to a conversation about critical points. Unlike in math when you just set the derivative equal to zero, the critical points being discussed at odd hours of the morning are much more difficult to solve for. What are they?

When is it, that critical point, where going to bed is better than continuing to study? When will the benefits of rest overcome the benefits of studying? A number of factors come into play, but the general consensus is (although Michelle appears to disagree) that although sometimes hard to find, there always is a critical point and at some point you should just go to bed. I ask all of you to remember this going into your finals. I know it may not be as big an issue in high school, but it's certainly something you'll face at MIT, so it's best to start the good habits now before they mess you up here.

Now, I'm back to studying for 18.03. If anybody feels like they can effectively explain how to solve:

Practice Exam 1, Problem 8. c)

I welcome an e-mail or an IM. e-mail me at snively [at] mit [dot] edu or g-chat me at jzzsxm [at] gmail [dot] com. (yes, I've looked at the answer in the back, no, it doesn't make any sense to me).

Good luck with the rest of the year!

Comments (Closed after 30 days to reduce spam)

I had a giant English portfolio project due today .. thus, subtracting the nap from 6am-8am .. I have been awake 31 hours. I performed a similar 39 hours last Fri/Sat for the same stupid project.. but now it is turned in.

Also, the answers for Exam I are on there

Posted by: donaldGuy on May 21, 2008

its 3 a.m. Here in India.....yet I'm not even halfway thru my review of AP Physics ..... In the past 2 months while self studying for all my APs I have experienced at least some of these things.....i also fell asleep while standing.......shhhhh.....don't tell ne1.......all this to to experience all the above things at MIT.....hehe....ironic ain't it???

Posted by: mohit on May 21, 2008

I didn't know people took Calc AB and then Calc BC the following year. Isn't that kind of a waste of a year since those subjects have a large overlap. Either way Calc BC is usually a two semester course in liberal arts colleges so MIT is indeed unique in that it covers the same topics in one semester.

Posted by: Michael on May 21, 2008

-to donaldGuy

I think Snively sees the answers. His question was an explanation of HOW to solve the problem.

Posted by: Derek on May 21, 2008

good luck on your finals ! hehe, the hard part : how to solve a problem, the good part : you won't forget it.

Posted by: 0 on May 21, 2008

I had the exact same type of question on my math final yesterday...but somehow a completely different answer. Why does it say you need a constant solution? Shouldn't a plain old solution be good enough?

Now I'm confused too. This is going to haunt me...

Posted by: Sarah '12 on May 21, 2008

My school doesn't give finals for AP classes ... yay!

Anyway, as far as I can tell the problem doesn't require a constant solution, but any one solution. It's easiest to work with if we can get rid of udot, so if we set u constant, udot = 0 and we get the equation in the answer.

Posted by: Reuben '12 on May 21, 2008

Reuben's right. A constant solution is the easiest to find because, as he said, the derivative of u then becomes 0...and A*u equals -[0 1]. The tricky part is then finding A, but the answer key explains how to do that. Once you've found A, invert it and you can find a constant solution.

(Disclaimer: I didn't get this immediately either - I got stuck after finding A - but someone asked about it during a review session.)

Posted by: Paul on May 21, 2008

Oh...that makes sense. I've never done it with a constant solution. haha, good to know.

Posted by: Sarah '12 on May 21, 2008

yeah...that practice exam made no sense to me...( i don't think that's a good thing) but i guess it's because I haven't taken that class yet. Hopefully, when I'm in Snively's shoes next year, I'll understand!

Posted by: Shion'12 on May 21, 2008

Hopefully when I'm in my shoes in 9 hours I'll understand!

Posted by: Snively on May 22, 2008

"sweatpants and flip-flop-clad knowledge harvesting beavers"

i love this i love this ilovethis!

For my three finals, I slept less than 11 hours over the last 80 hours or so. C'est la vie de MIT (excuse my lack of French knowledge, HAHA)

I'm SO happy to be done with finals though. Hang in there, everyone who has 18.03. It seems to be an epic cramming night tonight. Good luck!

Posted by: Oasis '11 on May 22, 2008

best of luck!!! Do well!!!! But keep blogging!!

Posted by: mohit on May 22, 2008

The epic battle between sleep and study continues.... Actually, what I found to work the best is to (attempt to) study well in advance (duh...but this never entirely works, thus the "attempt to"), and then stay up until midnight the night before, and wake up at four or so that next morning. An added bonus: you get to watch the sunrise before taking that exam (inspirational). It also helps to have a good ol' power mix of songs ready to go to keep you awake the morning of.

Posted by: 0 on May 22, 2008

Alright, I've just hit the 18 hour study mark and I'm going strong. Ok, well, about 15 of those 18 are actually studying, but it still feels like there's a lot of math in my head right now.

Posted by: Snively on May 22, 2008

wow....18 hours of studying....thats a job well done........keep going!!!

Posted by: 0 on May 22, 2008

18 hours? Snively, go to bed =P

Posted by: Piper on May 22, 2008

I suggest polyphase sleep. You could probably fit it into your schedule. I had school in the morning one week and in the afternoon the next, so this is what my sleep schedule looked like. I was able to function perfectly with only 4 hours of sleep. I eventualy gave up because I ended up with way too much free time than I could handle :D Especially because I was awake when everyone else slept. To get into schedule all I had to do is not sleep one day, so that I can easily fall asleep when I had to. Also, I was way more productive when I slept like this because school and home were clearly separated by 2 hours of sleep. Good luck.

Posted by: Sh1fty on May 22, 2008

Snively, how do you expect to be awake during the exam after 18 hours of non-stop studying? I would surely have a blackout!(not to scare you or anything:P)....Keep going and do well!!

Posted by: Ahana on May 22, 2008

"Why geeks make better boyfriends"? (Priceless btw)

Seriously, go sleep!

Posted by: Aditi on May 22, 2008

I could probably help you on some of those diff. eq problem

Posted by: Judy '12 on May 22, 2008

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