/sci/ - Science & Math

i meant (0*2)/0 = 0/0

>>14821696
Faggot. Maths is gay as are you. It won't change the fact you're a runt.

>>14821696
>Sqrt(4) = 2 and -2
nope
[math] \displaystyle
\sqrt {x^2} \ne \pm x, \quad \sqrt {x^2} = \left | x \right |
\\
|x| =
\begin{cases}
\;\;\; x & ,x \geq 0 \\
-x & ,x < 0
\end{cases}
[/math]

>>14821707
why not
-2 * -2 = 4

>>14821696
>ab/b = a
Wrong. And in the first step, lol.
Prove that [math]\forall a,b \in \mathbb{R} \quad \frac{ab}{b} = a[/math]. (protip: you can't)

>>14821765
>(ab/b) =a
>(ab/b)*b =ab
>a*b = ab
why is this wrong
>ab=ab

>>14821754
Not that anon but
negative 2 multiplied negative 2 times, hmm

>>14821754
most people on this board can't grasp that the general square root is not a function but a relation, in order to make the square root into a function you need some restrictions, so there are 2 valid square root functions, these are the positive and negative square root functions
so yes -2 * -2 = 4
but
2 = positivesqrt(4) =/= negativesqrt(4) = -2

>>14821696
>> (0*1)/0 = 0/0
division by zero is the arithmetic equivalent of pulling out your dick and pissing all over the chalkboard

>>14821805
You can prove anything starting with a false hypothesis.
>1=0
>there are 0 santa claus
>therefore there are 1 santa claus

>>14821894
what real numbers can be used for a,b that make (ab)/b = a false

>>14821904
b=0

>>14821911
> if a is real, a*0 = 0
> (a*0)/a = 0/a
> 0/a = 0/a
> a is all real numbers
>0*a/0 =a
>(0*a/0) *0 =0*a
>0*a =0*a
> 0*a/0 =0*a/0
> a = a
a is all real numbers
umbers then that includes

>>14821934
>(a*0)/a = 0/a
Wrong, division is not well defined for all real a. Do you know what division is?

>>14821696
All you've proved is that 0/0 = 0/0
>> (0*2)/2 = 0/0
You can't divide 0 with anything but 0, there is no half of zero dummy.

>>14821948
if a is real then a * 0 = 0
that takes care of all real numbers in place of a
im just dividing 2 equal terms by a

>>14821960
>You can't divide 0 with anything but p,there is no half of a zero
Yes I can.

>>14821980

>>14821992
>>14821960
sorry clicked the wrong post
i can divide 0 by 2
0/2 =2
if i have 0 lemons and i put all those lemons into 2 groups there will be 0 lemons in each groups

>>14821754
sqrt is a function, 1 input, 1 output
4 = x^2 (equation, not a function)
answer is +- sqrt(4)

>>14821996
someone give him the Nobel praise

>>14821805
By ZFT axioms, something cannot equal to different things. So if defined, 0/0 must equal to one thing only barring equivalent things. Otherwise, by transitivity of equality you can come up with contradictions, such as 1=2. Even if you ignore transitivity, since you have messed with multiplication and division by 0, you cannot multiply by 0 on both sides without first showing that multiplication by 0 is a function, (it is not anymore). Multiplication by 0 has become a many to many relation, and therefore you cannot multiply on both while still claiming equality. I mean just look at your final statement ab=ab, this is no more an always true statement in your definition of 0. 0/0 can take any value, including 1 and 2, which are not equal. Thus ab and ab are not always equal.

It's nice to question foundations, but if you are attempting to tackle them again, you must first consider, how your changes affect fundamental axioms and theorems in set theory and logic, and always use quantifiers and implications.

>>14821894
He assumed a proposition, and used it to obtain an equivalent proposition which (at least what he believed) is always true. That is a perfectly valid strategy to a proof. You are talking about vacuous truth which is using a false proposition to imply a proposition that may or may not be false.

>>14822726
It's literally the king of Sweden that puts Nobel prizes on people. I'm never going to get one.

>>14821877
>so yes -2 * -2 = 4
its -16 tho

1/0-1/0=1
2/0-2/0=2
3/0-3/0=3

0/0-0/0=0

>>14821696
>> ab/b = a
Only when b=/=0

>> (0*1)/0 = 0/0
Wrong.

>>14821696
This thread could be fun if the people in it knew how to troll with mathematics... but they don't. It's just a bunch of 19 year old sophomore idiots who barely passed high school and even then only on the honorary roll.

>>14821877
Seems like a function to me. Can you explain more, I'm not getting what you're saying

>>14821765
Doesn’t it work for 1 and 2?
ab/b=a
a=1,b=2
1*2/2=2/2=1

>>14821696
>0/0 = all real numbers. tell me why im wrong

Well, we know that "x*0 = 0" is true for all values of x.

So, conceptually, dividing both sides by 0 would produce "x = 0/0", which suggests that this equation "should" also be true for all values of x.

However, that conflicts with the rule that all binary arithmetic operators (such as addition, division, etc.) must be capable of being modeled as functions that map (R,R) to R. A function must produce a single, well-defined result for each input -- or else it must produce an "undefined" result if no such well-defined result exists.

Since we have no way of selecting which real number 0/0 "should" produce, we must default to the result being undefined.

Believe me, you DO NOT want functions to produce inconsistent or ambiguous results. (Same thing for operators, which are just a special type of function.) If even one function is badly-behaved on even one input, then it could poison every expression that it's used in. Once that happens, you'll potentially get inconsistent or ambiguous results in lots of cases. DO NOT GO THERE. Keep math pure. Keep math clean. Keep math consistent. You'll thank me later.

>>14826124
>Seems like a function to me.
The anon that you're replying to was talking about the square root function. However, what you posted was a graph of the square function. That's not the same function.

Graph sqrt(x) instead. You'll see that its graph is only the upper half of a parabola. Chopping off the lower half of the parabola was necessary, and it reflects the kind of restriction that he was talking about.

>>14826273
It is x = sqrt (y)

>>14821696
remind me again why functions aren't allowed to have multiple answers

>>14825343
>>> ab/b = a
>Only when b=/=0
illogical and arbitrary. try again.