/sqt/ Stupid Questions Thread

This thread is for questions that don't deserve their own thread.

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I'm at a community college right now. (It's actually a really good one for the science lower divisions).
I'm going for a BS in a biochemistry so I mapped out my course plan. I've never taken a physics course before and I will need a year of it when I transfer to uni. Should I take a baby physics course over a summer as a way to prepare for the relatively more difficult physics later on? Or would I be better off taking a math course as a way to boost my math skills? Would you guys recommend I take extra chemistry/biology classes to fill up my upper divisions or take on a minor in like computer science? Goal is to go to grad school btw.

I am absolutely torn between going into academia (math or statistics) or going into industry, making a lot more money and fucking with a relationship and shit.

Fuck

>Goal is to go to grad school
This is a question for your advisor then, do not take recommendations from internet strangers on a 6 year academic plan.
Physics is super math heavy so depending on your current skill level, it may behoove you to take some of it before taking physics. Only if you can jump straight into calculus though.

>I'm going for a BS in a biochemistry
Why are you fussed about physics/math then?
I mean, if you can afford it and want to sure. But I don't think anyone will really care about your physics grades.

>Would you guys recommend I take extra chemistry/biology classes to fill up my upper divisions or take on a minor in like computer science?

What do you want to do with your degree? For biochem, I'd probably fill up on extra chem/bio classes if you want to do something in science with it. If you dont, then yeah cs would be a good minor

Ask yourself what you want to do with your degree???? Then the answer should be clear

>Let A be a real n-by-n matrix. Show A is conjugate to a diagonal matrix only if there exists a basis of R^n consisting of eigenvectors
I'm not asking for a direct answer to this, but where the hell do I even start looking? I've only barely figured out how to show two different bases of the same Vector space are conjugate.

Think about how A acts on its eigenvectors and prove that they form a basis.

So if I understand eigenvalues correctly, they're effectively the scalars applied to vectors in V in the linear map T:V->V to yield v' or what-have-you, right?
So the only logical way for these to remain linearly independent (as a linear map) is for the eigenvalues themselves to form a basis of the vector space they're applying to?
Or am I missing a part/skipping ahead
I've only done computational stuff and nobody ever told me what the hell any of it meant

I have asked this in another thread with no answers.

What does it mean when the amount of equations and unknowns are the same? Does it make any difference if there would be one more unknown than equation? Does it mean that if the amount of unknowns is equal or less than the equations, then the unknowns are completely determinate? (that's what I'm thinking) Does this always hold true?

iirc Fewer unknown than equations (or the same) does not guarantee solvability, but more unknowns than equations does

Hmm. Learning some cs couldn't hurt. It would help to know if you are working with engineers and other programmers. Even if you don't minor, take maybe cs 1 and 2

>as a mech e
If you want to learn to program, it doesn't matter "for what."

It's most helpful to learn more than one language. I recommend C, racket/scheme, and haskell/ocaml. No programming language is very good, but if you learn enough of them then in a weird way they all become tolerable, except for python which is utter fucking shit.

Personally I would suggest staying away from C++ until you have two or three languages under your belt. Early in "learning to program" it's best to be able to separate the abstractions and their application from the peculiarities of an individual language and C++ is basically the most peculiar language in serious use. For that reason I think scheme or racket are the best beginner languages, but I don't feel extremely strong about it. A good language should have little syntax in my opinion so you can get to the meat of programming quickly. Forth and scheme are just about the most bare bones languages which nevertheless offer an extremely high ceiling.

Good languages: racket/scheme/lisp, forth, C
>why are these good to learn first
they have a very low surface profile, it's relatively easy to master the language in a short period of time, yet they are flexible enough to allow you to build powerful abstractions (C less than the other two, but it's still alright)
Bad languages: C++, Java
>why are these bad to learn first
They are too feature-rich and therefore difficult to start with when you are simultaneously trying to learn good ways to solve common problems in the first place. Arguably they get better when you are a better programmer but I think they are overrated even then.

>It's most helpful to learn more than one language. I recommend C, racket/scheme, and haskell/ocaml. No programming language is very good, but if you learn enough of them then in a weird way they all become tolerable, except for python which is utter fucking shit.
>Personally I would suggest staying away from C++

Fuck off /g/, you don't belong here.

C++. You can even include it into your Matlab code with MEX files. C++ is also what most everything is written in and you learn most of C at the same time.

Read: Programming: Principles and Practice Using C++ by Stroustrup
Then read: Data Structures and Algorithms in C++ by Drozdek

>take maybe cs 1 and 2

Why the fuck would you ever pay money to learn java?

here come the C++ apologists, they're like jehova's witnesses

Show that basis consisting of eigenvectors is linearly independent and spans your domain. Then you change to the eigenbasis using general change of bases and use the properties of c.o.b to get the conjugate relationship

>Should I take a baby physics course over a summer as a way to prepare for the relatively more difficult physics later on?

(Algebra based) Physics is just like theory in Gen Chem. If you could do one, you can do the other. University Physics assumes no background in physics so you're not going to be behind.

>Or would I be better off taking a math course as a way to boost my math skills?

Sure but your options are limited to linear algebra or proofs if you haven't finished calculus yet... (and even then you might need to get permission if they have calculus prerequisites)

>I'm able to jump right into calc, I've just been waiting until I start my calc/physics sequence to start because I don't want to be rusty.

You're not going to be rusty. The sooner you start calculus, the better.

Fuck off to /g/. You faggots have never even coded in C++.

Thanks boys

We have Introduction to Physics (101) -> General physics I & II -> University Physics I & II (Calculus Based)

Indians wipe their butts with their hands.

Might sounds retarded but how dirty is this, truly? What if you thoroughly wash your hands afterwards? Is there still a dangerous amount of poo-germs left?

Im trying to create a small scale rigid bosy simulation of an object rotating but im having a hard time think about how i can define the ibject computationally. Ive. Written my lagrangian out for the rigid body, but what would be the best way of defining the rigid body? Im using python and c++. I was thinking of drawing the part in blender, but idk how to export the data into something useful. Any thoughts?

Possibly because its interpreting the X input in something other than radians?

g(x) = √x-3 (square root sign extends over the minus 3)
The domain is assumed to be |3,infinity|
Why is this true since the domain is also assumed to be the set of real numbers and x=5 will result in √2. Or is there some other assumption that I'm missing?

If g is a real-valued function, then the “largest” possible domain is [0,infinity) because any x

√2 is a real number, what's the issue

I am working on a mathematical model of a disease, and have to give a talk to an audience of physicians.
How much math do doctors know? Should I go into some details of the model, or just gloss over them and focus on the results?

my professor is fucking with me
i submitted a paper a month ago and he still hasn't graded it
how do i deal with professors who fuck with me

visual explanation
youtu.be/PFDu9oVAE-g?t=3m

Why dont you use a finite element software?

Why the fuck do all calculus books define the "≥" relation as a relation in the real numbers such that satisfy certain properties (total order, x≥y implies x+z≥y+z and xz≥yz for z>0)?

If we were to define the "≥" relation as the relation between two numbers x and y such that their difference x-y belongs to the non-negative numbers, then ALL of the above properties could be proven from this definition.

So instead of stating like 7 order axioms we could just state the existence of a subset of R (named the nonnegative numbers) and the existence of that relation, and then prove all of those other properties

Jump straight into calc and physics will be a trillion times easier, you end up doing a lot of integrations.
Learn some basic python and maybe mathmatica, but it's not necessarily worth spending time in a class for. It's really simple to learn and you'll end up needing it to do number crunching.
C++ may behoove you if you stick closer to engineering.

I don't understand the answers in this fucking question. Shouldn't it just be zero considering ethane requires C and this formula has none of it?

Any graduate TAs or professors here?

Whats your love life like? How much time do you have to spend with your partner?

wat? Isn't [math]C_2 H_6[/math] ethane?

Yeah nvm I'm fucking retarded, I have no idea what I thought the C was.

what do you mean by relation? what kind of relation?

Retard here

I'm trying to calculate the length of a vector (-1, sqrt(3))
It's 2. I can draw it on a piece of paper and measure out that it's 2, I type it into an online calculator and it says it's 2.

The problem now is that I try to calculate the length myself it won't say 2.
Typing sqrt(-1^2+sqrt(3)^2) into a calculator or wolfram alpha or whatever will say sqrt(2).
So now I thought I'm and idiot it must have to do with the square roots and shit
sqrt(-1^2+1.7320508...^2) will feed me 1.41421 which is the square root of fucking 2

Please help I know I'm literally a fucking retard having trouble with like 6th grade math, this isn't homework but I just don't comprehend
The solution is probably fucking obvious to anyone that's not me, I just need someone to tell me

You're typing [math]-(1^2) instead of (-1)^2

It's because you're typing in -1^2 = - (1^2) instead of (-1)^2

Thanks friends
Turns out I'm too dumb to use a fucking calculator, I must have typed this wrong like 20 times into different calculators and online tools

hey man we've all made this mistake once in our lives. Don't be too hard on yourself and keep doing maths

Is it correct to say that atoms with more electrons are larger than atoms with fewer electrons? Or heavier?

It's literally the most common calculator mistake. There are threads about it here weekly or so. Not a big deal.

Thank you for the encouragement
I'll take this as a lesson to be more careful with my brackets

This was part of me calculating the angle between two vectors, what I got was 15 degrees off what I knew the solution should be, with the whole thing being rather straight forward and the small numbers it was quite irritating for a bit
Vectors are pretty cool

I feel kinda dumb saying this, but Linear Algebra changes the way you look at the world. It really is a beautiful field.

what do i do when my exponents have exponents

[math]a^{b^c} = a^{(b^c)}[/math]
[math](a^b)^c = a^{b*c}[/math]

alri that's fairly simple

Heavier is probably better. Or you could say the atoms with more electrons have more orbitals and so take up more space or something. Idk.

Electrons weigh next to nothing but atoms have the same number of electrons and protons so they would be heavier by implication
And they need more orbitals but I'm not sure how that would actually look in a 3D space

Say the orange car collided with the blue car, which both have the same mass.

If you know the initial speed and direction as well as the final speed and direction of the orange car, including the exact location where the collision took place, can you figure out the final direction and final speed of the blue car, or is there not enough information to solve for that?

Due to increasing electronegativity, moving from left to right along the periodic table generally results in smaller atomic radii.

You would need to also know the starting speed/direction of the blue car.

If that's what you meant they yes, you could figure it out using the conservation of momentum in the x and y axis'.

Work = q(change in kinetic energy)
So should this be (4.2x10^-9)*(2.2x10^-6)?
I read somewhere online that work is actually kinetic energy, or 2.2x10^-6 in this case. Why or why isn't this true?

work = change in kinetic energy = charge * field strength * displacement

You couldn't calculate work without the field strength, but since they give you the change in energy you don't need to.

how do i work these for tn= 2n-1 and n is greater than equal to 1.

on the first one i just do ti = (2(1)-1) + (2(2)-1) + (2(3)-1) right?

i have no idea how to do the second one or what that symbol is called

It's the same as the first, except you multiply every term instead of adding them.

14) the sum is equal to [math]t_1 + t_2 + t_3[/math]

16) the product is equal to [math]t_1 * t_2 * t_3[/math]

Provided you knew the initial momentum vectors for each car and supposinh any acceleration along the z axis (normal to Earth) is minimal, there is ALMOST enough information to deduce the final situation. We can apply conservation of momentum, but it would be even more useful to know HOW the cars interact with each other: elastically, plastically or other? Sometimes momentum goes to other stuff, like a bumper flying off. Energy is lost to friction and noise.

dude that hint is basically the whole theorem

Sonic the Hedgehog's mass is 34.9266125. When he's in a spinball, it takes him 3 seconds for him to fully charge up to go at the speed of light. How much force can Sonic exert?

When Sonic is charging up his spinball, he's spinning really really fast in place. I'm not sure if that might have something to do with the outcome. I also don't know if this is sufficient information to calculate his force. I'm not really a physics guy, so please explain if there is an answer to this question.

Yeah, sorry, I meant imply that there were no external forces like gravity, and the collision was completely elastic.

Okay so, what would you need to know in order to solve for the final momentum and direction of the blue car?

Would the initial momentum be enough? Or would you also need the initial direction? What if you had the initial direction but not the initial momentum?

(300000m/s)^2*~35kg = the energy necessary to reach the speed of light at that mass. To reach that speed at 3 seconds feom a standstill depends on the force of friction among other things.

What is the radius of his body in the form of a ball?

Uhh, no. It takes infinite energy to reach the speed of light.

I don't know actually. He's 100 centimeters tall, but in his ball form he's 50 centimeters if that helps. I don't think I have enough information.

>mass is 34.9266125
>go at the speed of light

Brainlet here, how the hell do I calculate two angles needed for equilibrium when I know 3 vector magnitudes and one angle? The numbers are:
Vector Magnitude (g) | Angle
168.6 g 0°
99.7 g ?
119.9 g ?

What is the best(fastest) way to reliably prep for the ACT and SAT considering I've been out of high school for nearly 8 years?

For the writing section, there is a set guideline that they look for. Look up how to pass the writing section and you'll be fine.

For the reading, you have to know a lot of vocab. They don't allow you to take advantage of suffix and prefix usage because they don't want you to be able to study for the exam, they want you to use you built-up vocabulary from many years of experience.

For math, it's mostly your innate logic combined with algebra and trig. At the very least, you can learn algebra and trigonometry before taking the exam.

Two questions concerning dentistry:
1. Is there any legitimacy to conspiracy theories about fluoride in the water?
2. Do fillings and dental fissures have health side effects?

Is ho3 2016 a second moon or a completely separate celestial body?

Why Mathematica keep using Log[e]? Isn't it just 1 ffs
Is there a way to change it?

Does Mathematica default log to base e, or is it like ti83/84 that defaults to base 10

Today I got my first Fluid Mechanics class and I noticed there won't be any conformal maps in the curriculum. Is there an introductory text or a book that focus on this application for conformal maps and maybe the underlying mathematical principles? I like mathematics and I was disappointed when I noticed it won't be covered in class. One with exercises will be much appreciated.

You probably just need to use a simplifying function around the results.

>1. Is there any legitimacy to conspiracy theories about fluoride in the water?
It is a fact that over-dosage of fluoride causes health problems. Wether the low dosage recommended to avoid cavities present long-term problems is a matter of debate. But there was a (anecdotal) case in my state where the water company put too little fluoride in the water. So, how much do you trust your company not to put too much in it?

Log to base e

Simplyify[] doesn't work

If you meet a random woman at the gym and she carries a negative recessive gene, isn't that just as dangerous as breeding with your sister that carries a negative recessive gene? Does the presence of similar negative recessive genes increase the likelihood of outcome? What if I carry a negative recessive gene that may cause Tonsillitis or something, and this woman I meet at the gym also carries a gene that may cause Tonsillitis, would breeding with her cause the same danger of Tonsillitis in our offspring as mating with my sister?

>If you meet a random woman at the gym and she carries a negative recessive gene, isn't that just as dangerous as breeding with your sister that carries a negative recessive gene?
yes

no your sister carries much much more recessive negative genes that you have too
the random lady shares only a few with you, but your sister a lot

But it's the same danger for Tonsillitis specifically, or the same "danger" for blue eyes specifically.

That's not the exponential e, dummy. ee for that.

Protip: Blue means undefined symbol.

How would you write the equations to solve for the seven currents in matrix form?

Oooh, I didn't knew that
Thank you kind user

Connect ground and V+ through a 6V voltage source, then set up mesh currents and solve simultaneously.

>Okay so, what would you need to know in order to solve for the final momentum and direction of the blue car?
>Would the initial momentum be enough? Or would you also need the initial direction? What if you had the initial direction but not the initial momentum?
Momentum is a vector, so if you know the momentum you (by definition) know the direction. If no momentum is transferred to the earth, the final momentum of the car wreck will equal the total initial combined momentum of the cars. Remember, momentum is p=mv, where v is the velocity vector and m is mass ( a scalar). The direction is included in the vector.