/sci/ - Science & Math

So what is wrong with this one?

>>6314726
jesus

>>6314726
If these are the people that fail engineering on their second year even when they're supposedly "good" at math that I have been told about, then I'm more confident.

Is that number 6 wrong?

Also I have never seen this kind of way of solving math problems

Don't muricans use these --> II

>>6314739
I think so. (6+6)/3 should be 4.

>>6314739
yes 6 is wrong, it should be x=2


most of them are retarded easy too

>>6314741
Have fun solving difficult math questions with Lia

>>6314739

It's 4. 3x=12

Divide both sides by 3

X=4

This is 5th grade math here.

Can you give me an example of HARD math problem then?

>>6314746

1+1=?

?=2

>>6314741
shit meant 4

oh wew im retarded too now, i guess

>>6314746
P=NP

>>6314751
What is P? And N?

>5:
>12*5*n = 0
>x = 0
THERE ISNT EVEN A FUCKING X

>>6314751
The only pnp's I know are transistors.
Please do explain.

>>6314753
>what is N?
LMOF
when someone writes X, do you then ask what is \? and /?

>there's a differance between / and \?

>>6314759
N=1 |=1/3, \=1/3, |= 1/3

>>6314751
P=NP
N=1


Where is my fields medal?

>>6314753
>>6314758
http://en.wikipedia.org/wiki/P_versus_NP_problem

>>6314804
Also:
http://en.wikipedia.org/wiki/Millennium_Prize_Problems#P_versus_NP

Saw this gem yesterday

>>6314824

no big deal, he just fucked up decomposing the fraction

/sci/'s status: rekt

>>6314726
>intelligenceissexy

hhehe

>>6314726
^ _ ^

>>6314746
Infinity - (-1/12)

>>6314871

Troll aside, but Budhism and Taoism have concepts in them (like the big bang for instance) that date 2000b.c.

How could they know?

>>6314746
Assume an idealized, perfectly running watch with a sweep second hand. At noon all three hands point to exactly the same spot on the dial. What is the next time at which the three hands will be in line again, all pointing in the same direction? The answer is: Midnight.

The first part of this problem-much the easiest-is to prove that the three hands are together only when they point straight up. The second part, calling for more ingenuity, is to find the exact time or times, between noon and midnight, when the three hands come closest to pointing in the same direction. "Closest" is defined as follows: two hands point to the same spot on the dial, with the third hand a minimum distance away. When does this occur? How far away is the third hand?
It is assumed (as is customary in problems of this type) that all three hands move at a steady rate, so that time can be registered to any desired degree of accuracy

>>6314996
Trick Question, The Watch Isn't Real

>>6314928
I wish Isaac Newton was here to give his view on that solution
I really am curious as to what he would think

Three men rent a hotel room. Each pays $10 for a total of $30 spent on the room. The next day the hotel owner tells the three men that they over paid for the room as it only costs $25. The three men tell the owner to give them each a dollar back and he can keep two dollars.

If you do the math, each man paid $9 a piece for the room for a total of $27. The owner kept $2 which brings the total to $29.

The question is where did the other dollar go?

AHAHAHA this thread is people trying and failing to solve 6+6=3x for x. /sci/ really is in trouble.

>>6315021
x=4

>>6315021
>>6315039
Am I smartest on /sci/ now?

>>6315003
He would think it was fucking stupid

>>6314928
=infinity+1/12

1/0=infinity
therefore
infinity*0=1

>>6314996
a hand?

>>6315021
x=3.99999...

>>6315009

U wot?

What's going on here?

>>6315009
That's actually very clever. The error though is in comparing money spend to money gained. So originally each guy has 10. But they give them to the man so they have zero. The hotel owner has 30 at this point. He then gives each man back 1, so he has 27 and each man has 1, for a total of 30. It still holds up that he kept 2 because if he had given back 5 he'd only have 25, not 27.

I like math but I don't claim to be good at it. I'm awful.

Pic related, test problem last year I got wrong.

>12/3 = 6
>can't into mental math

>12 * 5 * n = 0 -> x =0
>can't into different variable

>to practice math, practices solving linear equations
...

>>6315085
I remember you from that thread where you posted it, in the end what was the correct answer?

>>6314902
that's funny because people on the inside would be floating around, unable to feel any gravity

>>6315102
Unit tangent should have been -4j and unit normal should have been 5i.

It must have been an algebra mistake but I'm still not sure where.

>>6315085
That's horrifying.

>>6315085
this isnt even that hard, it just looks scary

>>6315159
It's not hard in principle. It just results in a lot of algebra and it is very easy to make mistakes.

>>6315096

>>6314799
Nope. You didn't take into account the possibility that P = 0.

No medal for you.

>>6314799
well, you do have a medal in fields, since if you were working in a field that or P=0 would be true.

>>6315224
P=NP
If P = 0 and N =1 that's still true

>>6315206
didn't know this one.pretty cool.
I'll use it as an example for my "students"

>>6315294
what's the catch?

>>6314751
n=1 lyl

>>6315210
>>6315211
What am I missing here? I can't figure out what is wrong.

>>6315352
lolol

>>6315352
One too many parentheses.

>>6315350
the first one is okay, the second is still wrong

1-.999... =/= 0.0000...1 because there is no difference

still funny though

>>6315385
0/10

>>6314799

P and N aren't variables. P stands for Polynomial time, and NP stands for Non-Polynomial time.

>>6314977
aliums :^)

>>6315130
Are you sure that's the correct answer?
I think I said it last time, but everything I try doesn't give me that.

On a quick look you can see that you forgot to actually take the square root when calculating the unit tangent.

somebody help me with this please, I have an upcoming exam

determine all x € R for which the following equation holds true:

1/x + 1/|1 - x| > 0

how do I generally tackle that kind of problem?

>>6315221
Using ... in the middle like that indicates that there are finite terms... moron.

>>6315401
That's what's written on my paper.

>>6315409
>pls respond

>>6315420
I'd say tot ask your professor if that's indeed it, because the unit tangent seems to be -1j, and the unit normal 1i.

>>6315192
>>6315196
>>6315202
>>6315206
>>6315210
>>6315211
>>6315213
>>6315217
I can't find what's wrong with any of these. Is math broken?

>>6315394
Atlanteans

>>6315409
Graph it.

>>6315506
but I won't be able to graph it in the exam with just a pen and paper

>>6314902

>>6315479

First one uses integration by parts wrong.

Second one states without proof that if a ~ b (a congruent to b) then x^a ~ x^b. This is not true. (a^x ~ b^x is though)

Third one doesn't really apply as the only way you could write the x's out is if it were just a constant integer, in which case the derivative would be 0.

Fourth one assumes without proof that if f(a) < g(a), for some a then f'(x) < g'(a). This is not true.

Fifth one states that 1^i is 1 but does not prove it.

Sixth one is abusing the periodicity of sin and cos, something to the power of 0 is 1, so in complex exponents 1^1/2pi would be 1^1/0 which doesn't really work...

Seventh I can't even see what that mess of symbols was supposed to mean.

And the last one is abusing re-arranging infinite series (which can change their value). But it is valid in some applications of maths (string theory etc)

>>6315210
Well first off, 1^i =/= 1

>>6315581
>Seventh I can't even see what that mess of symbols was supposed to mean.
The upside down A means "for all".
So ∀ n ∈ Z means that the statement holds true for all integers n.

>>6315612

Yea I got that, I mean the mess in the third line after the implied symbol

>>6315409
1/|1 - x| is always positive.

So find where 1/x is more negative than 1/|1 - x|.
Obviously this can only happen when x is negative, or 1/x wouldn't even be negative.

So let's say x = -a where a is some positive number. 1/|1 - x| would equal 1/|1 + a|, and 1/x would equal -1/a.

Because the denominator of 1/|1 + a| is larger than that of 1/a, the absolute value of 1/a is always greater than the absolute value of 1/|1 + a|.

So, the function is negative for all x < 0.

>>6315624
try x = -1/10

then you get for
1/x + 1/|1 - x| > 0

-10 + 10/11 >0 which is obviously not correct

>>6315624
>>6315649
sorry I'm an idiot

>>6315624
would rearraranging the terms generally be a good idea?

1/x + 1/|1 - x| > 0

1/|1 - x| > -1/x

|1 - x| = |x - 1| > -x

or did I make any mistakes here? plus is there any way to get rid of this obnoxious absolute value shit or get it on both sides?

>>6315192
obviously the mistake here is that he failed to recognize that 1+1+1+... = 1+2+3+... = -1/12

>>6315662
a > b =/=> 1/a > 1/b

It's easy to find a counterexample.
e.g. 3 > 2, but 1/3 < 1/2.

>>6315949
Maybe he forgot to invert the inequalities?
1/a > 1/b
a < b