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Best calculator for Finite Math? by Willard Dunkle - Wed, 21 May 2014 02:08:59 EST ID:BfGCwHN9 No.14015 Ignore Report Reply Quick Reply
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I need some opinions.
>>
Alice Nossleway - Thu, 22 May 2014 19:23:04 EST ID:CRoP6qUg No.14024 Ignore Report Quick Reply
Finite math? I think any will do. Shit, I'm a few courses away from my Ph.D. and I only have my dad's old calculator from the 80's. Rarely use that either. There's not much need for a calculator in mathematics, more of an engineering thing.
>>
David Trotman - Fri, 23 May 2014 00:41:02 EST ID:GQFtkEgG No.14025 Ignore Report Quick Reply
>>14024

Mathematicians compute using computer software anyway. Stuff like Mathematica, Maple, Matlab, Octave, etc.

>>14015

Use your computer as long as you can. Then beat up some poindexter on the day of the test and take his calculator. He will have thought about the choice of the calculator so you'll know it'll be good.
>>
Walter Trothood - Fri, 23 May 2014 03:36:15 EST ID:SzH+rmP/ No.14026 Ignore Report Quick Reply
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>>14025
You can beat me up, but you will never take my calculator! I AM the calculator! HAHAHAHAHA!


Zero by Nathaniel Drangergold - Sat, 17 May 2014 20:42:30 EST ID:UKjRrFaw No.13976 Ignore Report Reply Quick Reply
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Why can't you like, divide by zero and shit?
20 posts and 3 images omitted. Click Reply to view.
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Emma Grandcocke - Tue, 20 May 2014 08:04:45 EST ID:gxFYvDAi No.14010 Ignore Report Quick Reply
>>13995
I like that exercise. I'm more a logic guy than a numbers guy and a bad one at that. But I do know a few things; I used to think 1/0 = infinity because of the limit exercise, but know I see it in better terms - because of it's external implications, it violates the law of non-contradiction were it possible, as that reduction to absurdity shows. Which means to ask what x divided by zero is basically like asking what happened before time or what's north of the north pole. Just meaningless, but removed enough from concrete experiences our primitive monkey brains don't get it.

now if you excuse me I'm gonna go get stoned because shit that was an overdue epiphany
>>
Esther Snodwill - Tue, 20 May 2014 16:00:55 EST ID:DMle3oF7 No.14012 Ignore Report Quick Reply
>>14004
I am not sure that's true. The Proportion of a circles diameter to its circumference is not made up. It's the property of any perfect circle, but maybe a perfect circle doesn't exist, so you would be right, but basically you are saying that all math is ultimately inherently wrong.
so i think the notion should be shoved up where the sun don't shine all together.
>>
Graham Grimhall - Wed, 21 May 2014 08:17:25 EST ID:MTIV7/tU No.14018 Ignore Report Quick Reply
>>14012
Indeed, a perfect circle does not exist in our physical reality.
>basically you are saying that all math is ultimately inherently wrong
At the risk of sounding like the typical math nerd, please define "wrong". Math describes the way we, as humans, perceive reality. This is how it is artificial, because our perception isn't perfect. Reason and logic are human constructs too, so who's to say a demonstration provides an actual proof?

I worded that awfully.
>>
Thomas Chenkinwat - Wed, 21 May 2014 09:34:25 EST ID:DMle3oF7 No.14019 Ignore Report Quick Reply
>>14018
>At the risk of sounding like the typical math nerd, please define "wrong".
distorting reality. now we could go to /pss/ to discuss reality but i'd rather not. in fact i have and it's confusing :S
>Math describes the way we, as humans, perceive reality. This is how it is artificial, because our perception isn't perfect
well, that would fit the bill for any science, so the notion is hyperbolic.
>>
Phoebe Cussleman - Wed, 21 May 2014 10:23:05 EST ID:CqjA2pA6 No.14020 Ignore Report Quick Reply
Because division is the inverse of multiplication.

4/0 = x --> 0*x = 4
and 0*x = 0

So it goes to shit


I need a function by Phyllis Honeycocke - Mon, 19 May 2014 16:10:55 EST ID:s2Z0Pypj No.14002 Ignore Report Reply Quick Reply
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I need a function f(x)=y which will give me Y=(1, 2, 3, ..., 10) for X=(1, 2, 3, ..., 10) but also for X=(11, 12, 13, ..., 20), X=(21, 22, 23, ..., 30), etc. Is it easy to do?
>>
Hugh Deshcocke - Mon, 19 May 2014 16:34:49 EST ID:SzH+rmP/ No.14003 Ignore Report Quick Reply
y = [(x - 1) mod 10] + 1
>>
John Gummlemork - Tue, 20 May 2014 08:37:08 EST ID:I6SRHOrD No.14011 Ignore Report Quick Reply
>>14003
Thank you. I forgot you can "just modulo". ;-)


Public School Victim by William Hebblewere - Wed, 16 Apr 2014 02:01:09 EST ID:DXsM+Oxu No.13910 Ignore Report Reply Quick Reply
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Like many kids I had shitty teachers, that only knew how to teach via text book, I didn't learn how to read a standard clock till 7th grade on my own accord, and it wasn't until after school that I tried to get better at spelling and punctuation.

Math was by far my worse subject in school. I failed essentials math grade 11 3 times before my mother just did it for me. at almost 25 I am now finally ready to get better at mathematics.

I love science and math being the language of the universe, wish to understand the universe better.

What I really suffer at is multiplication and division, but if anyone has little tips or hints on adding and subtracting that would be great too.
Any books or things that help adults who are mathematically stunted.
17 posts and 2 images omitted. Click Reply to view.
>>
James Panningnore - Mon, 19 May 2014 09:24:49 EST ID:gxFYvDAi No.13999 Ignore Report Quick Reply
>>13971 basically every word I starred ultimately came to us via French.

English is kinda like a rope - just calling it Germanic is too over simplifying, only acknowledging one thread in thing. It's really more complex than one thing came from one thing. There's something called horizontal transferrence, it's not a family tree, it's a family bush.

Like, we are a somewhat welshy grammar under what happens when a V2 language goes SVO. Our vocab is Saxon, Latin, Jutish, French, Dutch, Greek Danish, Norman, Frisian, Angle, with bits of Yiddish and Gaelic thrown in, with idioms mixed mostly of French, Welsh, Yiddish, and Saxon origins.

Ours is a magnificent bastard tongue.

>>13997
Maybe all this is better for /lang/ but just as a general thing:

https://de.wikipedia.org/wiki/Aspekt_(Linguistik)

try to find your native language on the left and read as much and as many different types of it as you can (especially if you ever want any hope at comprehending Chinese, which doesn't use tense in favor of aspect almost exclusively, opposite German).
Comment too long. Click here to view the full text.
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nuet - Mon, 19 May 2014 10:54:38 EST ID:GHTRtQRe No.14000 Ignore Report Quick Reply
>>13910
i LOVE math there are all kinds of tricks to remeber how to multiply and divide. im sure theres more online then what i have.

theres one for multipling anthing by 9, your far left pinky finger is 1 what ever number you multiply by 9 you put that finger down and that gives you your answer the number before your finger thats down and the number of fingers after. for example 5x9 you would put down your left thumb and your answer would be 45.

a lot of math is memorization and repetition, if your study and practice you wont even have to think about it the numbers come right to you. i would suggest getting a multiply table. those are supper handy
>>
Esther Snodwill - Mon, 19 May 2014 21:02:12 EST ID:DMle3oF7 No.14005 Ignore Report Quick Reply
>>13997
essentially, you mean x*9 = x*(10-1) = 10x-x;

>>13999
i read a quote that said e^pi=0 is proof of god or devine creation, lol i guess though there is a reasonable explanation that links the two constants.
>>
Esther Doddleshaw - Tue, 20 May 2014 00:12:16 EST ID:SzH+rmP/ No.14006 Ignore Report Quick Reply
>>13999
Jeez, what state did all this happen?

>>14005
>i read a quote that said e^pi=0 is proof of god or devine creation
Actually, it's e^(i*pi) = -1. This is Euler's identity. http://en.wikipedia.org/wiki/Euler's_identity

And as for it being a proof of God's existence, you're probably conflating Euler's identity with a troll proof alleged to have been concocted by Euler in an apocryphal tale (from third paragraph): http://en.wikipedia.org/wiki/Leonhard_Euler#Personal_philosophy_and_religious_beliefs
>>
Emma Grandcocke - Tue, 20 May 2014 07:42:35 EST ID:gxFYvDAi No.14009 Ignore Report Quick Reply
>>14006
California. The middle, east, and north of the state are super conservative (well, libertarian in the north's case) - LA and Frisco may be the liberal paradises conservatives love to rag on about but the rest of the state really isn't like that at all. The only reason they have the clout over the state they do is because of a mix of good old fashioned corruption and the fact that more people live in LA than most nations (it would be 72nd in the world were it to secede) let alone the bumfuckistan of the rest of the state.

Some more tidbits about it - where I live there's more (real) cowboys than all the fake or real I ever saw in Texas, NM, or AZ (family in TX). The rodeo's a major city-wide event. They replaced all the rock stations except the oldies one with country. Lots of Armenians, Hmongs, and Mexicans officially overtook 50% of the population. All of the medicine is either rich people's or Catholic, rendering abortion basically illegal etc. Fun place. Good food though. send us ur water pls


Back to math Euler's identity as proof of god was more likely a joke that was misunderstood - it's been called beautiful by a lot of people. Then again, with the Gödel thread I guess anything's possible.


xjxjxj by Hannah Fimmerderk - Sun, 18 May 2014 12:34:31 EST ID:GQFtkEgG No.13990 Ignore Report Reply Quick Reply
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What does xj mean in this problem? This notation doesn't seem to be explained by the book I got the problem from: Mendelson's Introduction to Topology.
>>
Ian Pittbury - Sun, 18 May 2014 16:27:57 EST ID:qz3c7Bt+ No.13991 Ignore Report Quick Reply
xj is x using j as an indexing function. Hence xj = x_j(1), x_j(2), ...


Russell's Paradox by Wesley Cliblingstone - Sat, 03 May 2014 17:52:43 EST ID:8PJ0nVdr No.13957 Ignore Report Reply Quick Reply
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Can any of you mathmagicians explain this paradox to me? I'm too stupid to understand the wikipedia.
3 posts omitted. Click Reply to view.
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Cyril Pizzlestock - Tue, 13 May 2014 22:10:17 EST ID:iMUpn1NT No.13966 Ignore Report Quick Reply
>>13958

This was a question in my friend's discrete math class. The answer is not yes and not no.
>>
Fuck Farrystark - Fri, 16 May 2014 18:42:57 EST ID:gQ1/L8ZJ No.13973 Ignore Report Quick Reply
>>13966
... There wasn't a question. And 'not no' is 'yes', yes?
>>
Clara Mishfoot - Sat, 17 May 2014 07:08:59 EST ID:V2nhYpJ2 No.13974 Ignore Report Quick Reply
>>13973
Not cyril, but I don't think "not yes" in this case would equal to no.
These interpretations are subjectively intuitive, you are free to disagree as long as you present your view:
If an answer is both yes and no, then either of them is good.
If an answer is both yes and not yes, then whatever we are inspecting does not depend in any way from our answer.
If an answer is neither yes nor no, then there is no answer and we have paradoxal situation.
>>
Simon Buzzdock - Sat, 17 May 2014 12:46:06 EST ID:5fuPW64F No.13975 Ignore Report Quick Reply
>>13974
This is dependent on the model of logic you are using
If you are just using classical two valued logic then not yes (true) equals no (false) and not no (false) equals yes (true)
but if you are using some abstract many-valued logic system with four truth values, then I guess you are free to interpret however you like
>>
Cyril Febbleforth - Sat, 24 May 2014 13:46:10 EST ID:Fj/YvlCk No.14030 Ignore Report Quick Reply
>>13974
>Not cyril, but I don't think "not yes" in this case would equal to no.

Then not yes is not no and not no is not yes?


PHYSICS, BITCH by Angus Goodbanks - Wed, 14 May 2014 16:14:56 EST ID:I2hi9ugw No.13967 Ignore Report Reply Quick Reply
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So I need to find the force of friction acting on a vehicle.
The vehicle is going 25km/h (6.94m/s) and comes to a stop
over a distance of 10m.
The mass of the car is 1250kg.
I'll lay down some formulas in the next post but this is what was stated in the question.
>>
Angus Goodbanks - Wed, 14 May 2014 16:19:25 EST ID:I2hi9ugw No.13968 Ignore Report Quick Reply
so Ff = μFn
and
Fnet = Fa - Ff
W=F(parallel) Δd
p = mv (if that is worth fuckin' anything)
Ek = 1/2mv^2
Fg = mg
and in this case
Fn = mg
>>
Angus Goodbanks - Wed, 14 May 2014 16:22:00 EST ID:I2hi9ugw No.13969 Ignore Report Quick Reply
g = 9.81m/s^2
The # I got for Fn = 12 262.5N
and I think
-Ff = Fa - Fnet
so
Ff = -Fa + Fnet
>>
Shit Wondlewater - Wed, 14 May 2014 22:24:50 EST ID:dtJRvm7a No.13970 Ignore Report Quick Reply
They didn't give you the coefficient of friction, so all the equations you posted are irrelevant. The only equations you need to solve this are F = ma and the kinematic equation v_f^2 - v_i^2 = 2ad. From your problem, v_i = 6.94 m/s, v_f = 0, d = 10 m. So plugging in these values and solving for a gives you an acceleration of a = -2.41 m/s^2 (negative just means deceleration). To get the magnitude of the force of friction just multiply the magnitude of the acceleration by the mass of the car F_f = (1250 kg)(2.41 m/s^2) = 3010 N (to three sig figs).


Choice Under Uncertainty by Reuben Bollerworth - Sat, 26 Apr 2014 12:26:50 EST ID:W+YT9wqY No.13942 Ignore Report Reply Quick Reply
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Hi! I just had an Economics exam some days ago and I didnt know how to answer something:

John eats apples and carrots. His preferences are represented by
U(a,c) = f(a) * f(c) where f is strictly increasing

He can buy apples and oranges at (pa,pc) which are random variables that can take the values (3,1) or (1,3) with 50% of probability each.

Another option he has is to buy the apples and oranges before the realization of the random prices at (2,2)

Will he go for the certain option?
The thing is, I would usually try to determine if U is concave, since that would mean this guys is risk averse... I dont know how to use the fact that f is strictly increasing besides the fact that this means he always prefers more to less.
>>
Fucking Hadgenet - Sun, 27 Apr 2014 18:39:18 EST ID:hE9drZeG No.13946 Ignore Report Quick Reply
>>13942
hmm this is tough,
my intuition says he would select the (2,2) option because of diminishing marginal returns on apples or oranges. I don't think having that 3rd apple would be better than having a 2nd orange instead, but because so little info is given that can't be strictly true.

The expected number of apples and orange is 2 each (50% probability to go 3,1 or 1,3), so as you mention they are essentially complement buckets. If you assume risk aversion then one would go for 2,2 since it's a sure thing, + the marginal utility argument isn't too bad either. idk just some random thoughts
>>
Walter Pickbanks - Sun, 27 Apr 2014 20:38:22 EST ID:W+YT9wqY No.13947 Ignore Report Quick Reply
>>13942
yeah, tomorrow I will have my test.

I think maybe just had to demonstrate that the uncertain lottery can be obtained by the certain one by a mean preserving spread of the distribution fuction and then say that this implies that the uncertain one is dominated (Second Orderd Stochastic Dominance) by the first one. Then conclude that any utility maximizer individual that is risk averse would go for the certain one. The thing is, I did not see this as an option in the exam because I couldnt find a way to demonstrate that this individual is irsk averse.
>>
Angus Pedgeberk - Mon, 28 Apr 2014 23:37:36 EST ID:3BOoYnsp No.13949 Ignore Report Quick Reply
>>13942 I have my exam. I couldnt attend the class but the professor told me that the proof goes by demostrating quasiconvexity and therefore that the random option is not Second Order Stochastically Dominated by the safe one... or something like that.

Delicious cake for anyone posting the answer before me.
>>
Fuck Hillyson - Sat, 10 May 2014 19:18:13 EST ID:vk6kR3B3 No.13962 Ignore Report Quick Reply
>He can buy apples and oranges at (pa,pc) which are random variables that can take the values (3,1) or (1,3) with 50% of probability each.

I had a hard time trying to understand what you meant with that wording. It took me a while deciding whether pa referred to price of apple or probability of apple until I settled with price.

Due to the function U(a,c) handling both parameters a and c equally, it does not matter which is which. Therefore prices (3,1) and (1,3) yield the exact same values from function U, assuming money is a limited constant value, hence the probability of 50% you mentioned is meaningless.

We're left with two options, which involve no luck or chance. Either we settle with the value of U given by prices (2,2) or either (1,3) and (3,1).

Let us denote money by m, amount of groceries by s and pa=k, pc=n

m = ka + nc
s = a + c

Before I go on, I remind you that the apples and carrots are treated equally, there is no difference if the amount of each switch places.
Comment too long. Click here to view the full text.


volume of revolution about y-axis by Edward Pickdock - Wed, 30 Apr 2014 15:01:13 EST ID:gs0WQAqP No.13950 Ignore Report Reply Quick Reply
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sup /math/

When solving for volume of solid generated by revolution about y axis do i have to solve the given equation for x?

Find the volume of the solid generated by revolving about the y-axis the region bounded by the curves y = (3x+22)/ sqrt(x^3+11x^2+4), the x-axis, and the lines x = 0 and x = 1.

How would i set this problem up? solving for x in this case sounds impractical
>>
Nicholas Bungershaw - Thu, 01 May 2014 00:29:30 EST ID:7IVXNODr No.13951 Ignore Report Quick Reply
It will be an integral f(x)=(3x+22)/ sqrt(x^3+11x^2+4) bounded from 0 to 1. Wolfram-alpha gives some good visual if your not sure what it's going to look like.
>>
Nicholas Bungershaw - Thu, 01 May 2014 00:33:23 EST ID:7IVXNODr No.13952 Ignore Report Quick Reply
>>13951
oh, just fyi x values will be the bounds. In problem when they're not given you'll have to solve for them.
>>
Alice Fanningpad - Thu, 01 May 2014 00:36:06 EST ID:dtJRvm7a No.13953 Ignore Report Quick Reply
>solving for x in this case sounds impractical
It is. Do this: http://en.wikipedia.org/wiki/Shell_integration

So for your case, you should take the integral from 0 to 1 of 2(pi)*x*y(x)*dx.
>>
Alice Fanningpad - Thu, 01 May 2014 00:47:47 EST ID:dtJRvm7a No.13954 Ignore Report Quick Reply
>>13953
Comes out to 8(pi).
>>
Barnaby Casslewet - Thu, 08 May 2014 17:21:16 EST ID:m+wesBpj No.13961 Ignore Report Quick Reply
Just use the shell method, make sure your 'slices' with width delta Y are parallel to the Y axis. Seems counter-intuitive at first but it works.


study by blop - Fri, 02 May 2014 15:32:38 EST ID:D6XeU0jB No.13955 Ignore Report Reply Quick Reply
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hey /math/ i am starting to go to school for my GED and would like to find a better way i can work on my math skills at home can some one give me a good site to study pre algebra?
>>
William Fommerhood - Fri, 02 May 2014 17:27:16 EST ID:dtJRvm7a No.13956 Ignore Report Quick Reply
https://www.khanacademy.org/


Complex Analysius by Priscilla Masslebury - Sun, 27 Apr 2014 08:52:54 EST ID:GKq/pGEr No.13945 Ignore Report Reply Quick Reply
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Hey math/

What is the significance of Im[ f(u(theta)) ] = 0 ?

What can we say about f(z)? u(theta) forms a continuous closed loop in the complex plane.

In return, tits.
>>
Matilda Bosslestock - Mon, 28 Apr 2014 14:56:09 EST ID:MTIV7/tU No.13948 Ignore Report Quick Reply
>>13945
Seems to me like the image of the loop is in the real axis.


Class options for next semester by Faggy Bashspear - Tue, 15 Apr 2014 11:21:02 EST ID:D8I2lPwU No.13901 Ignore Report Reply Quick Reply
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I'm a sophomore math major, and next semester I plan to take abstract algebra and either probability or dynamical systems. I'm thinking probability is probably (heh) more practical, but dynamical systems looks like a lot of fun. Do you guys have any input? Should I just take what appeals the most to me?
8 posts and 3 images omitted. Click Reply to view.
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Edward Savingwater - Sat, 26 Apr 2014 01:04:07 EST ID:5fuPW64F No.13938 Ignore Report Quick Reply
>>13937
>-1/12 is the sum of the natural numbers
You are the first person to mention this in this thread.

>type up a reply on 420chan that is longer than the necessary google search
I agree.
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Nell Sushfield - Sat, 26 Apr 2014 04:17:11 EST ID:Dk8yywxc No.13939 Ignore Report Quick Reply
>>13938

>didn't read the thread
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Jenny Billerchine - Sat, 26 Apr 2014 11:39:45 EST ID:dtJRvm7a No.13941 Ignore Report Quick Reply
>>13937
I bet you also believe imaginary numbers are legit and .999... = 1. ;)

You're getting way too rustled over the most common /sci/ troll thread topic.

http://youtu.be/w-I6XTVZXww
http://youtu.be/E-d9mgo8FGk
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Nell Sushfield - Sat, 26 Apr 2014 13:08:49 EST ID:Dk8yywxc No.13943 Ignore Report Quick Reply
>>13941

0.999... does equal one if you are in a system that doesn't allow Infinitesimals, for instance the regular real numbers. If you are in something like the hyperreals, than 0.999... != 1. And yes, I have no problem with imaginary numbers, they're clearly worthy of study.

Stuff like the Ramanujan summation and interpreting these series through the Riemann zeta function is not a "legit" summation, it is a property of the partial sums. We don't know whether the sum 1-1+1-1+1-1... will stop at an odd or even position, so they gave it a value 1/2. That is not completing the summation, it's a property of the partial sums.

The reason I decided to address it is because I've seen it all over the place, not just this site. People like the asshole in that first video will perpetuate this with the goal of "oh science is so cool this stuff adds up to -1/12" while what is really happening is that he's presenting people that aren't familiar with the situation a skewed image that is completely false for the assumption of the average youtube viewer that he is "really" summing to infinity and getting -1/12. I'm not saying that this stuff isn't worth study, but when you have some person with a shit face grin adding up a divergent series to get a negative number, it's doing more damage than anything. Complete misinformation.
>>
Edward Savingwater - Sat, 26 Apr 2014 15:44:19 EST ID:5fuPW64F No.13944 Ignore Report Quick Reply
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>>13943


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