Can those brilliant professor types really look at those long ass equations on the whiteboard?

Okay, I know I probably need to step away from the TV.

You know how in those (usually) sci-fi flicks, you’ll have some nutty genius looking at a giant whiteboard filled with one singular large equation? And they just sort of stand there looking at it thinking THIS works here but THIS doesn’t work there. etc…

Can they do that for real or is that just a tired Sci-fi troupe?

Yes they can. And so could I when I was in college taking differential equations. It’s not unlike asking if someone who learns another language if they can read a book. Today after 30 years removed from the class and twenty years removed from using any high level math at work I too would look at a board full equations and be fairly dumbfounded by most of it.

Sure –

After working with them a bit various terms sort of become their own symbol in your brain – you don’t really need to focus on the details of everything in the equation, you see the way it all fits together. “Long equations” aren’t constructed randomly – they are made up of a bunch of meaningful sub equations.

Like an automotive engineer looking at a car – he knows all the details about the engine, but he can still take a step back and think about how the whole car fits together.

Or an architect with a building, or an aeronautic engineer with the space shuttle, or, or, or …

I’d say it’s even more analogous to a serious musician, especially a composer or conductor, looking at a multi-part music score (sheet music) they’ve never seen and “hearing” the symphony or whatever in their head – and noticing musical “problems” and coming up with creative “solutions.” Yes, some can and do do this.

Yup, that’s pretty much it. When you’re really in the thick of it (and it’s your equation) it’s really not hat hard at all. Each one of those numbers and letters and greek letters and symbols and shapes all mean something and the result you get at the end is something your expecting. So if you get 17 Feet Per Second and you were supposed to get -400F/s[sup]2[/sup], it’s a matter of figuring out where you flipped a sign or something got something got lost from one line to the next. And yes, when you find that, you look like a mad man when you get excited and start carrying that flipped sign from one line to the next to see what it does to your result.

-Joey P
Math Major.

Heh, it’s interesting you say that. I was also going to post a thread asking if a really proficient piano player can nail a piece of sheet music with out having heard or read it before hand.

Heck, I’ve had plenty of classes with such equations. I’ve written them in line of my various jobs (although on paper – often on more than one sheet. I learned fom my first advisor to number the sheets, so I don’t get them out of order.)

I was watching the original Sam Peckinpaw version of Straw Dogs at MIT. Dustin Hoffman plays an astrophysicist in a home out in the English countryside. He has a blackboard set up in the living room with one of those soul-killing equations on it.

At one point his wife has a fight with him. as she walks by the blackboard, unseen by him, she erases a “+” sign in the middle of that welter of figures and changes it to a “-”.

One guy stood u in the audience and exclaimed:

“I’d KILL her!”
But the real kicker is that, in a later scene, Hoffman’s character walks by the board and out of the corner of his eye sees somethinbg wrong. After studying it for a moment, he changes the “-” sign back to a “+” sign with a single swift stroke.
The equation isn’t just on the blackboard – it’s in his head. The blackboard is just a convenience, and in a pinch you can do without it, like those oriental kids who work addition and subtraction problems with an abacus that isn’t there, moving their fingers to shift imaginary beads. I know – I’m not an astrophysicist, but I’ve manipulated ridiculously long math expressions. You can read 'em because they’re not just onn the blackboard.

I remember when I corrected a Vietnamese student at the board (way smarter than everyone including the teacher) by showing that he had a sign flipped and the class stood up and cheered! :smiley: He made a big show of thanking me as well. Needless to say, the math bullies stayed away from me after that incident, less they too be corrected. :smiley:

Picture says a thousand words.

And yes — where it is legible it is readily understandable. And this is from a person who doesn’t speak the same language as the professor.

There was a great moment in an episode of The Big Bang Theory in which Sheldon and Raj were staring at a blackboard filled with equations while the intro to “Eye of the Tiger” played.

I remember one “take home/group” exercise from a Linguistics class. Well, I remember doing the exercise. My partner and I had a solid week to do the thing and we even had a spare classroom with blackboards running the entire length of all four walls (except, of course, for a break for the door). We filled the boards. And apparently we only made one mistake on it. Honestly, it looked like the math expressions from the “mad scientists” in the old Saturday morning cartoons.

Yeah, plenty of fields have their own written language, so to speak, that doesn’t look at all like English or Spanish or even Arabic, and those conversant in it can read it very well, usually.

Relevant xkcd.

Something that may be obvious to some but not others.

The entire board is usually NOT one long ass equation. It’s usually one equation stated many different ways.

The first equation is a base equation which is usually easily understood by the people who are using it.

Then the equations below it have components of the previous equation replaced with equivalent equations or values.

simple example

X = 2y + 4Z (first line) possibly a well known law of Ferdinomics

but it’s also known that y = 2Q +5 and z = 3Q+1 (from Boogerism mechanics)

So the second equation subs those in and gets kinda hairy looking

X = 2(2Q+5) + 4(3Q+1) (second line)

If you saw the second line equation by itself you might not have much faith in it but you know it’s good because the substitutions are valid.

X = 4Q + 10 + 12Q + 4 (third line)

you wouldn’t have a lot of faith in the third line either except for the fact that algebraic principles show it to be a valid result of calculations in line two

X = 16Q +14 (last line) (Schmeldo’s law of Q’s)

So starting out with a definition of how X relates to Y and Z you have determined that X has a relationship directly to Q.

“Now that desk looks better. Everything’s squared away, yessir, squaaaaared away.”

holy shit :eek:

I have a block against readingIPA language notations, I couldn’t figure out word one if it meant my life and that of everybody hold dear. Might as well be in chinese. And the damnedest thing is I can and do shift my accent according to the people around me. If I hang out with southerners, I end up sounding like Sampiro, if I am up in Maine, I end up sounding like a refugee from a Stephen King novel. :smack:

TLDR (ha almost punny)

what happens is even worse. you take some real long ass equation and call it some Greek letter. then that goes into another real long ass equation and then you call that some Greek letter. then that goes into another real long ass equation and then you call that some Greek letter.

i’ve been tempted to get a roll of paper and write some out, but i’d be pissed if i made a mistake or formed some characters poorly.

Awesome. Two funnies in one thread.

Even better: Two funnies in one thread about… equations!

Same here. Worst for this from undergrad was “Mechanics of Machinery.” We learned how to derive the equations of motion for mechanical linkages of arbitary complexity. For the most part, it was a matter of adding up a bunch of relative velocities/positions/accelerations until you had connected the velocity of your particular point of interest relative to (the unmoving) ground. You tended to end up with equations that had a lot of sines and cosines of various angles, with those angles expressed as arcsines and arccosines of various ratios of lengths. It looked complicated and took a lot of room on the paper, but if you were the one working the problem, you could parse it out and make sense of it.

Worst from grad school was “optical signal processing and introduction to holography.” Optical signal processing involves the use of laser light and lenses to instantly compute 2-dimensional Fourier transforms, convolutions, and autocorrelation functions (functions that require a LOT of processing power if done digitally), and has a lot in common with holography. The math was insanely complex and flipped back and forth between the space domain and the frequency domain, with 2-dimensional integrals that spanned the width of the blackboard. I struggled to make sense of it back then, and I doubt I could make much sense of it now - but yes, these equations were all built up in a rational manner from meaningful components, and if you sat and studied it you could (usually) parse it out.

To expand on what others said earlier, meaningful equations are not random jumbles of symbols. The symbols form “phrases” and match symmetries. Once you’re familiar with a general problem area, you can quickly look at an equation and get a sense for what it means and if there’s something not right.

For example, I walked into a tutorial session, because I was going for lunch with several of my friends there afterwards. I noticed on the board a term like “K H P + P K[sup]T[/sup] H[sup]T[/sup]”. Without knowing precisely what they were doing, that equation really made me itch, so I had to ask the instructor if was correct. Their answer wasOops, that’s wrong, it should be “K H P + P H[sup]T[/sup] K[sup]T[/sup]”.

It’s not that the original wasn’t a well-formed expression, it’s that the correct one follows a pattern often see when describing real systems. It’s no different than a musician seeing certain chord combinations written out and thinking “huh, do they really mean that? or is it a typo”.

+1
(from this musician)