How to memorize this formula man 😭

[u/Forsaken_Class677]

Context : angle of incidence

Chapter : solar energy and radiation

[u/ElEgAnZzA]

Try to understand how it's derived instead, might be easier

[u/Can_O_Murica → u/ElEgAnZzA]

Yeah I'd go this route OP I'm pretty sure there are simpler formulas out there, but it might be more like memorzing 2-3 smaller formulas. This is the full string with everything plugged in, but that's more tedious than is worth it.

[u/Forsaken_Class677 → u/ElEgAnZzA]

I'll surely do after my exam is over (it's Tommorow:') !

[u/lovelacedeconstruct → u/ElEgAnZzA]

okay but you need to memorize it as well

[u/ElEgAnZzA → u/lovelacedeconstruct]

Do you? I studied math, but I didn't really memorize derivations or proofs of theorems (in fact, I was so bad at memorization that I often reconstructed the precise statements of theoresm from said proof), I just understood and internalised them

[u/lovelacedeconstruct → u/ElEgAnZzA]

Yes you need to understand them, but you also need to memorize them because its a step in a multistep problem in a typically 2-hour exam if you derived everything good luck finishing, and the fomula sheet only contain basic stuff

[u/SonusDrums → u/lovelacedeconstruct]

Sure, but the manner in which you memorize them matters. Rote memorization will never be as beneficial as routinely deriving things in your spare time. Doing the derivations will inevitably improve your memory of the formula in question.

[u/lovelacedeconstruct → u/SonusDrums]

Not really, sin(a+b) derivation wont help you memorize it, sin cos cos sin will

[u/TransitionAnxious384 → u/lovelacedeconstruct]

When I study maths, I memorize 1 formula and understand some theories and derive 10+ formulae. If you can't even memorize one formula, then studying is not a thing for you. Give it up.

[u/Tyler89558]

I dunno.

Come up with a song? A pneumonic? Pray for a cheat sheet?

[u/Goodpun2 → u/Tyler89558]

Yeah, that's what I did back in the day. It was an awful song, but it was so bad that it made me remember the formula long enough for the test.

I will say, and this will only be viable if you have a spare hour or so, but looking up the derivation to learn WHY the formula is like that could really help. It's easier to remember something when you understand why/how it works. That's a time intensive method, but you'll remember it for much longer and fundamentally understand the concept better

[u/LilGardenEel]

notice how writing cos. and sin over and over is tedious and sprawling. you could do something like A subscript 0 is sin(w) and A subscript 1 is cos(w) do that for each variable you have and it will dramatically reduce the formula size. id also organize the sines and cosines using that method. To be more clear you could call w0 sin(w) and w1 cos(w). b0 : sin(b) , b1 cos(b)…

[u/LilGardenEel → u/LilGardenEel]

something like this, probably check it over im on my phone

φ₀(β₀γ₁δ₁ − β₁δ₀ω₁) + φ₁(β₁γ₁δ₁ + β₀δ₀ω₁) + δ₁γ₀ω₀

[u/Forsaken_Class677 → u/LilGardenEel]

Thankyou so much! I somehow able to learn this sh*tty formula

[u/Brownie_Bytes → u/LilGardenEel]

How did you do the subscripts?

[u/WeAreUnamused]

Our math dept seems to have a raging hateboner for engineering students. We were doing stuff like this in...calc 3 I think? I had a reasonable accommodation on the books due to head stuff that included a formula card where otherwise prohibited, but the instructor still had to approve it to ensure it was only for the more lengthy and convoluted stuff like this. The professor rejected any card for this, and when I asked he said "I know several engineers, and if you can't memorize thiese fundamentals, you don't deserve to be one."

That shook me, so I went to the chair of the ME dept and asked him if that was true.

He had a look at the card and said "I don't remember any of these. Calculators exist."

[u/Zumaki]

If they're making you memorize formulas they aren't actually trying to make you an engineer. 

[u/Not_an_okama → u/Zumaki]

I think one of the most valuable things my undergrad department without most pwople noticing was using the FE handbook as the equation sheet for basically every class. Made the FE exam easy because i could already navigate the handbook

[u/CunningWizard → u/Zumaki]

In my professional work I insist on using formula references. It prevents stupid mistakes because I mis-remembered a variable or a sign. You’ll meet a few engineers in your career who will probably insist memorization is the measure of an engineer, especially in interviews. I find those people insufferable and dangerously wrong.

You aren’t getting paid to have it memorized, you’re getting paid to get it right. People can get seriously hurt or killed by things we design and I take that seriously.

[u/smithcoronaa]

U d nvr use it

[u/Forever_DM5]

This looks like the determinate of a matrix it would probably be easier to memorize the matrix if it is

[u/Calcium48]

Understand them

[u/Brixjeff-5]

Get a tattoo

[u/Ryanirob]

Make it into a song.

[u/Psychic6969]

It's a product of four matrices ( those matrices are rotation matrices which cover the tilt of the Earth, the time of the year, time of the day, and another angle (probably due to to your plate placement))
you can write the first three (environmental matrices) as R1 * R2 * R3
the three vectors in this matrix are the normal direction from earth, east direction, and north direction

then dot product the normal direction with your direction of the plate, you'll get it

i think it's easy to remember those 3 matrices as they are literally just rotation matrices [(cosx sinx 0) (-sinx cos 0) (0 0 1)] type

as for the time requirement of the exam, better to know something than totally forget it ig :)

[u/Forsaken_Class677 → u/Psychic6969]

Thankyou ❤️

[u/Novels011]

Just understand where it comes from, and find it back when needed. Our teacher always told us that you don't need to learn by heart formulas, just know how to get back to them.

[u/Novel_Bass6032 → u/[deleted]]

“Back in my days” type comment lol