/SQTDDTOT/ IS DEAD

>correct answer
>clearly showed working

Looks like whoever marked your paper is the brainlet. Go up to your lecturer and politely ask them to explain why you were marked down.

they probably expected you to mention an apparent problem at 0, where ln(x) goes to -infty.

see, you just say ln(x) x^3 is 0 when it tends to 0, and that's not obvious. should have computed the limit.

Ohhhh okay. That makes sense. Thank you. I must have been so preoccupied with whether I could integrate the function that I didn’t check for that.

It is (a) if the distribution is Absolutely continuous.
Not sure if (b) can happen.

If you just use it to rinse the water away, you might as well use a dehydrateting agent, such as Sodium sulphate (anhydrous, of course) or the more common calcium chloride (always anhydrous) to purify the ether.

Anyone?

I'm writing a short hand-in in latex
the equations are number as 1.1, 1.2 and so on, I want them ordered as 1, 2, 3

How do I do this?
I use the package amsmath

Hypothetical question

Say we are able to use quantum entanglement for FTL communication. If I want to tweet to the people of Earth, from a planet near a black hole, how would time dilation affect the information going from one point to the other?

am I failure at life if I didn't go in depth into science, math?

I need to draw a random number from a normal distribution with a mean of zero and variance of C

In Matlab I can get a number from the standard normal distribution using
a = randn;
To get what I'm after do I just need to do
b = randn * sqrt(C);

help me I've gone stupid

but shouldn't the one with the Br be higher priority rendering the molecule (S) one double bonded O plus one O equals 3 oxygens, which is still less than the atomic weight for Br

same for the other two, should they not be (R) instead?

>Assuming we break this law of physics
>How would this law of physics then work

Take the space on which X is defined to be discrete an thus every X will be continuous.. So it does depend on the distribution...

I have no clue, but why don't you just rinse with demineralised water and dry it out?

>Missing dx

mathworks.com/help/stats/normrnd.html

HOW AM I SUPPOSED TO INTEGRATE THIS GARBAGE?

I'm trying to create a food network where each node is a recipe and I need a (better) weighting scheme.

Edges between recipes are drawn if the recipes share an ingredient.
The thickness of an edge is determined by the intersection over union of the ingredients,
i.e. how many ingredients the recipes share divided by the total amount of ingredients in the two recipes.

This system would be better if ingredients were weighted; some ingredients are really popular, almost all recipes include salt.
Therefore salt should not add as much to edge thickness as an obscure ingredients.

At the moment I'm using this to determine the weight an ingredient adds to the edge thickness.

ingredientFreq = (ingredientCount / allIngredientsCount)

ingredientWeight = - ln(ingredientFreq)

It works to the extent that
salt = 3
beef stock = 8
yucca root = 13
With salt being the most popular and yucca root being the most obscure ingredient, appearing only once.

I used this formula because it seemed intuitive. Any better ideas on how to do this?

notice that [math] \frac{\partial}{\partial x} \ln(1 + xy) = \frac{y}{1 + xy} [/math]

We use an ultrasonic cleaner at work and a solution I can't remember the name of

What exactly is particle "spin" explained in a way that a brainlet like me can understand?

Noob here, working through a precalculus textbook to get the fundamentals down. One of the questions is to find distance between the points (-2/3,3/2) and (7/3,2). I got sqrt(9.25) as my answer. The book said the answer is sqrt(37)/2. I spent like an hour trying to figure out how they got that answer before realizing they both evaluate to the same thing. Kek. Anyways I still can't seem to figure how they arrived at sqrt(37)/2 rather than sqrt(9.25). Anyone help explain to me? If I were taking a course, which answer would be considered superior if that was a question on a test?

I did notice that friend, the problem is what comes after since I have a bound of 0

When you're doing classical mechanics you find you need different things to work out the future behaviour of the particle, at its simplest form things like position and momentum. For more complex problems you may need more properties like charge or angular momentum.

It was realised from experiments that quantum mechanics needs a property of particles that had never been observed in classical mechanics. This extra degree of freedom was found to have a number of properties that make it similar to particles having an intrinsic amount of angular momentum, even if they're point particles with no real rotation.

This intrinsic angular momentum is fixed for particles of each type and changes how the particle behaves in electromagnetic fields, as you might expect for a classical particle with angular momentum in an electromagnetic field. It also ends up having other more wacky effects that have nothing to do with a classical form of 'intrinsic angular momentum', regardless they called it spin.

massless rope and caster
frictionless caster
frictionless table and frcitionless inclined plane
you need horizontal F > 10N to move m3 if you hold m1
m1=m2=m3=5kg

I need to know the angles where m1 and m3 move together when the thing gets released
Also, the maximal Force of the rope where m1 and m3 move together

Thank you for Help/Ideas

Br would have the highest priority, but OH would have the second highest priority. If you were to rank that it would be Br>OH>CO2H. Which corresponds to R.

You have to remember that R/S is not like E/Z, the priority is assigned based on the FIRST point of difference. While E/Z would be simply weight.

If that is the boundary, the next integral's result is too big, the boundary is probably just the square

I'm a bit rusty and confused right now.
Let's say I have a function [math] \phi : \mathbb{R^n}\to \mathbb{R} [/math] and an affine transformation [math] T : \mathbb{R^n}\to \mathbb{R^n} [/math] with [math] T(x) = Ax+b [/math]
Am I correct with the following statement?
[eqn]\nabla ( \phi~ \circ~T)(x) = A(\nabla \phi~ \circ~T)(x) [/eqn]

I'm gonna fucking kms if I ever have to take another digital systems class after this semester. I just got my midterm back, and I received 68% on it.

How do I solve something like (3sqrt(2))^2 without a calculator?

(a*b)^2=a^2*b^2

Thank you, user.

Chain rule.
[math] D_x(\phi \circ T) = D_{Tx}\phi \ D_xT = \nabla\phi (Tx) \ A [/math]

that wouldn't fit from the dimension though, right?
gradient is nx1 , while A is nxn.
Wouldn't [math] D_x [math] be divergence?

>Wouldn't [math] D_x [/math] be divergence?
For divergence, you use div. [math] D_x f [/math] means the derivative of f at the point x. If f is a scalar function, then some people use [math] \nabla f (x) [/math] .

>gradient is nx1 , while A is nxn.
Nope, gradient is 1xn.
Generally, if you have a function from R^m to R^n then the derivative at a point α is a linear map from R^m to R^n which can be represented by a nxm matrix. (in the R-->R case that linear map is just [math] x \mapsto f'(a) x [/math] and the matrix is just f'(α) )
This linear map approximates f around that point (it is the best linear approximation): [math] f(x) \approx f(a) + (D_a f) (x-a) [/math] when x is close to α. You may also see this as: [math] f(a+h) \approx f(a) + (D_a f) (h) [/math] .

forgot to say: h close to 0

but isn't the OH if we rank by priority number 1 since it is directly connected to the stereogenic carbon? (the one pointing up I mean)

I would be forever grateful if you ELI5, I've been trying to understand it all day but now I just can't make sense of it

What is the algorithm for +?

Or Just The Plus Function In General.

Like, 1+1 = 2

But what is just ? + 1 = ?

>Wouldn't [math] D_x [/math] be divergence?
I fucked up here. I forgot the definition of divergence and actually meant [math] D_x f = (\nabla f)^T [/math]
Lets just say [math] \nabla f = (\frac{\partial }{\partial x_1}f,...,\frac{\partial }{\partial x_n}f)^T [/math]

Would [math] \nabla(\phi \circ T) = A^T\nabla\phi (Tx) [/math] be right then?

>Would ∇(ϕ∘T)=AT∇ϕ(Tx) be right then?
Yep. [math] A=BC \iff A^T = C^T B^T [/math] .

thanks alot
due to a double fuckup I managed to write a correct code even though I assumed it was [math] A\nabla \phi [/math] and I was wondering why it still worked lol

kek
A was symmetric, right?

[math]A=\frac{B \text{C9369}}{A^T}=B^T \text{C9369}^T[/math]

nah, I was implementing some finite elements code and at some point you need to integrate [math] (\nabla \phi)\cdot (\nabla \psi) [/math] over some triangle.
T was the transformation from the standard triangle ((0,0),(1,0,(0,1)) to the one I needed to integrate over, which lead me (falsely) to integrating [math] (A^{-1}\nabla \phi)\cdot (A^{-1} \nabla \psi) = (\nabla \phi)^T ((A^{-1})^TA^{-1})\nabla \psi [/math]
And like a total idiot I was just pulling the inverse out of the bracket without switching the matrices around, so my mistake from before canceled out

I mean when you ask for a better weighing scheme for recipes the sarcastic asshole inside me says maybe use the actual weight of the ingredients in the recipe. Either as a fraction of the total in the recipe or of the total ingredients in the network. There are a lot of recipes that have the exact same ingredients but in vastly differing ratios. My best example is the wide array of butter/flour/eggs/sugar mixtures that make cakes.

What's the objective of the network? Because I can see a freakish modern taxonomy of food in your future that sounds pretty fun.

Let Australia Become Your Home.

Why Ignore Simon In The Process? You Are Learning How To Become Many-As-One.

But You Are Not Respecting The Host, Which is simon.

ANL語言障礙是一個傳統開始由西蒙·特洛伊科斯格羅夫。 現在,該輪到你了。
這個人有自閉症:治愈中國愚蠢。 〜學者時,西蒙·特洛伊科斯格羅夫。 主笑話!
西蒙·科斯格羅夫特洛伊 - 孤獨的人

精神分裂症是自閉症患者。 治愈是多神論的平移的單一文化!

What?

Do you have to keep posting as Anonymous? Really makes this hard.

Okay, the - sign in MY post name is actually Simon Troy Cosgrove.

So the 0-X

0X's

Try that.

I'm sorry you must have misunderstood.
What does your entire post have to do with mine?
Why did you reply to me?
Why do you think anyone cares about your dumb name?
What does Australia have to do with food networks?

Australia Has Undiscovered Food For China.

Australia Natives Gift Discovery Of Mathematica To China.

China Desires Spice For Kitchen, We Have Many New.

It's some stupid namefag thinking that being retarded through 10 layers of irony is not retarded.

Do as you do with all namefags, ignore and move on.

OK can do.

You can if you want, but australia has already won.

Really trying to invite the world to us. You guys just keep wanting to fight over... well, trinkets. Shiny baubles.

Literally, nothing of interest. Shitposting is only of value because you guys derive value from it, but if you want to do science that actually makes you happy then 'Veeky Forums' (Lit. Dead Friends In Chinese (Traditional))

Hello China. You Move Many Ways.

Thanks for your reply! Weighting the ingredient by its physical weight/volume or "importance" to a recipe is a good one, although I'm not yet sure how that could be meaningfully quantified (a few ml of soy sauce will change a dish a lot more than a few ml of water)

The dataset I'm dealing with is the "What's cooking" dataset from kaggle, which provides recipe ingredients (without any quantity) and their cuisines, so it won't be anything too fancy. I'm mainly working on this network to see if I can derive cuisines from recipes and vice versa for a graph theory course.

Talking about "freakish modern taxonomy of food", there is a company called spoonacular that has created a food ontology/taxonomy with 300k+ recipes, which is nothing short of insane.

That is amazing to hear. China will be pleased, I am sure.

Which degree/s will allow me to research and develop the biological side of robotic limbs/organs?

If matrix A =
[2 -1]
[-1 1]
what are two examples of a non-zero matrix X such that AX = XA?

I've got X = I which is obviously IA = AI = A, but what's another example?

A

What approach to topology would be best to learn if I'm interested in the topological side of condensed matter physics?

Point-set or algebraic?

AA = A^2 though.

I, -I, constant*I
A, A^2, A^constant
A^-1, A^-2, A^-constant

9.25 = 37/4

>which answer would be considered superior
the one you think of firat

If f(a+b) = f(a) + f(b) why is it that f(0) = 0. Assume a and b are integers.

Fuck fraction work why even teach it over work with decimals?

Had to help with an elementary school word program

1/3 of a lawn was left to mow, he mowed 2/5ths of what was left, what fraction of the entire lawn did he mow.

Maybe I'm getting dumb, but I literally just drew it out and got 2/15.

If we assume the lawn is 100 and 33/100 is about 1/3rd then 33 * .4(2/5) = 13.2 so he mowed 13.2 / 100 of the lawn. or .132 about what 2/15 gets you

1/3 *2/5 = 2/15

>1/3 *2/5 = 2/15
>Maybe I'm getting dumb
I knew it. Why did I think I had to divide it...Stupid word problems fuck school.

[math]f(a) = f(a + 0) = f(a) + f(0) \\
\implies f(a) - f(a) = 0 = f(0) [/math]

Every stereocenter in that image is wrong, as you said.
The theory say so, chemdraw and my organic chemistry book confirm that, so basically it's like pic related.

suppose you have a subset S of the set of natural numbers from 1 to n in which no two distinct elements can be divisible by k. what is the largest size of S?

Are there any 1st order continuous odes that are chaotic and only use elementary functions?

Besides "Topics in Algebra", what should I use to teach myself finite fields for coding theory? Are there any recommended video lectures? I took Advanced Linear so I have some background, but my degree is EE so it's a bit out of my expertise.

amazon.com/Coding-Information-Theory-Graduate-Mathematics/dp/0387978127

Can anyone tell me if I've done this right? I'm trying to find the flux through a point h units directly above the center of a disc of radius 1 with constant irradiance. I also expect this to scale linearly with the disc's irradiance, so I didn't include that, but my intuition there might be wrong.

man and i took it from the clayden book, thanks for putting my mind at ease user

thanks

Any polynomial expression in A.

0+0=0
f(0+0)=f(0)
f(0)+f(0)=f(0)
f(0)=0

What prevents the human bone from just slicing through the flesh of our feet when standing/jumping/stomping?

it's not made of knives

It is n minus the multiples of k that are less than n.
Euclidean division: n=qk+r
It is n-q.

Oh wait, add 1 cause you could have one element that can be divided by k if n is greater or equal to k.
n-q+1

How does it handle this day in and day out? How does it not dig itself through?

...

Any able to help with some metric spaces business

Two things you can try:
1) Compute the distance between fn and fm for arbitrary n and m. Is that compatible with a convergent sequence?

2) For which x does the sequence converge pointwise? Do you know any results relating pointwise convergence and convergence with respect the sup norm?

Check out [math] d(f_{n+1} ,f_n) [/math]
You will find out that it's not converging to 0

>to 0
The question is whether it converges to 1/x not 0 and it doesn't.

i'm talking about the metric converging to 0 not the function

Suppose that f_n converges uniformly against a function f then f must also be equal to the pointwise limit.

[eqn]\lim_{n \to \infty} f_n(x) = \begin{cases} 0 & \text{if } x = 0 \\ \frac{1}{x} & \text{else } \end{cases} [/eqn]

but [math] f(x) = \begin{cases} 0 & \text{if } x = 0 \\ \frac{1}{x} & \text{else} \end{cases} \not \in C([0,1]) [/math].