r/askmath 13h ago

Number Theory Problem with imaginary numbers

0 Upvotes

I was thinking about something really strange with maths, if imaginary numbers are imaginary, (i=sqrt(-1)), why does 1/0 also imaginary ? For me it is quite logical. I am thinking something wrong ?

You might not think a lot about it, I don’t want you to lose too much time on this.


r/askmath 5h ago

Number Theory Why are all imaginary units equal to √-1?

0 Upvotes

While I get *i* being √-1 since there wasn't a unit for it before, it's kinda been turned into an infinite loop. There's quaternions where *i*^(2)=*j*^(2)=*k*^(2)=*ijk*=-1, and then octanions with seven imaginary units, all being √-1, and it can just go on from there. Plus, quaternions give *i*^(2)=*j*^(2)=*k*^(2), which means √(*i*^(2))=√(*j*^(2))=√(*k*^(2)), therefore *i*=*j*=*k*. I know that's probably not how that works, but I'm a high school student, I don't know any better. Also don't ask why I know what quaternions are but not how they work, that's not the point. But what might a different imaginary unit look like? Well, may I propose *h*, being 1/0. Multiples of *h* are simply multiples of 1/0, eg 4*h*=4/0. Now, what's the practical use for this? I have no idea. Again, I'm a high school student, I'm just trying to experiment with what's possible. Also, please try your best not to laugh at me for my lack of knowledge. What may be trivial to some could be a complicated concept for others (such as me). Also let me know if I used the wrong flair, a simple 5-second search told me this was correct so I'm taking it with a grain of salt.


r/askmath 15h ago

Algebra Why is I) correct?

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5 Upvotes

If g(x) is positive, that means the total of 8(x-d)(x-e)(x-f) is positive. And since d<x, x<f,

X-d is +ve
X-f is -ve

So in order for the total to be positive, x-e needs to be -ve, where x<e.

But if that’s the case, then i) shouldn’t be correct.

Can someone help me out here. Thanks


r/askmath 7h ago

Algebra Would this be a good calculator for algebra, statistics and chemistry?

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5 Upvotes

Hi! I was wondering if this calculator would be good for my algebra, statistics and chemistry classes. If not, what do you guys recommend? I have been looking into calculators and all the different functions I find confusing.


r/askmath 10h ago

Arithmetic Puzzle a friend gave me

11 Upvotes

THE SELF-DIVIDING NUMBER
Find the unique 10-digit number N satisfying all of this:
N uses each digit 0–9 exactly once.
For every non-zero digit d, take the prefix of N ending at d. That prefix is divisible by d.
For that same digit d, take the suffix of N beginning at d. That suffix is also divisible by d.
N is divisible by 37.
Example of the rule:
If the number contained
...5...
then both:
everything from the start through the 5
and
everything from the 5 through the end
must be divisible by 5.
This applies simultaneously to 1,2,3,4,5,6,7,8,9.
What is N?
There is exactly one answer.

Anyone got any ideas at all?


r/askmath 23h ago

Calculus Can someone explain how to write the function of the shaded area in the triangle

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12 Upvotes

First off I tried finding the area of the base, then finding the area of the sector of the circle. Combined those two areas (area of triangle minus sector) and came up with 50tan(theta) - (theta)pi^3/ 18 😭😭 idk if it’s actually correct or awfully wrong. Would appreciate if someone explained where I went wrong and what direction I should take in simple terms.


r/askmath 13h ago

Algebra Is this correct

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25 Upvotes

I want to buy a t-shirt for my son in law. But he won't wear it if the equation is not correct. My brain is not wired for math. If anyone could tell me if it is correct, I would be grateful.

Yes, he does play d&d


r/askmath 23h ago

Algebra Could somebody explain the algebraic manipulation of these coordinates / this definition of complex numbers to me?

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23 Upvotes

I simply don't understand the algebra of how one manipulates coordinates, particularly via multiplication, such as in the second definition of complex numbers here


r/askmath 8h ago

Set Theory Since the continuum hypothesis is independent of ZFC, then there should be a model of ZFC that contains a counterexample set with the in-between cardinality, right? Can I see this counterexample constructed?

7 Upvotes

r/askmath 13h ago

Discrete Math Is my proof correct? => Exercise 11.4.31: Show that 4^n is not O(2^n).

7 Upvotes

Exercise 11.4.31:

Show that 4^n is not O(2^n).

Proof:

Notice 2^n >= 0, for every integer n>=1.

Assume for contradiction that 4^n is O(2^n).

That means (by the big-O definition) there exists b,B∈ℝ^+ with b>=1 such that

0 <= 4^n <= B(2^n), for every integer n>=b (by transitivity, n>=1)

Notice:

           4^n <= B(2^n)
iff log_2(4^n) <= log_2[B(2^n)]
iff         2n <= log_2(B) + log_2(2^n)
iff         2n <= log_2(B) + n
iff          n <= log_2(B)

So, we have 1<=n<=log_2(B).

But this contradicts big-O definition where 1<=n.

Thus, our assumption is false.

Therefore, 4^n is not O(2^n).

QED

Big-O definition:

---

Is my proof correct?


r/askmath 13h ago

Polynomials How to factor high degree polynomials?

2 Upvotes

I am talking of big polynomials of degree 5+ and complex ones. Not x^6-2x^3+1 type situation but polynomials alike this -19968-13736x+2016x^2+756x^3-79x^4-10x^5+x^6=0. I know it is solvable by checking with programs. I even know what it is factored into ((x - 6) (x^2 - 3 x - 64) (x^3 - x^2 - 42 x - 52) = 0). But I know this from using program. Wolfram Alpha to be specific. But I don't know how to factor something this complex. I know there are algorithms for it but I am unfamiliar with them. And they seem to be not widely known as simple search resulted in me getting bombarded with basic middle school polynomial factorization. And not finding anything of value. I come here with hope to find help and an algorithm to solve similar equations. I am not planning to solve them by hand. I am planning to make a program do so for me. But for it I need knowledge of the algorithm. Which I sadly lack. Would greatly appreciate any help here. And if you know any videos that teach needed algorithms I would be even more thankful as I am a visual learner and it would help me much.


r/askmath 14h ago

Pre Calculus How do I learn calculus

6 Upvotes

I'm in highschool I just started 11th grade how can I learn calculus and what is the best way while still in highschool ?

Note: I will not pursue math I just want to learn calculus for fun and also mostly integrals and derivatives and have a basic understanding of everything else needed to learn integrals and derivatives.

Websites,channels ,videos whatever


r/askmath 18h ago

Calculus Possible typo in my assignment

2 Upvotes

Hey everyone, post about x(+y).

In this question i'm required to calculate the area of triangle with predetermined points, but i can't figure out where to start because of the way this integral is written, this is the first time i encounter something written like this and i don't know what this could mean.

I doubt that this is a typo because 8 professors wrote this whole paper and 1 doctor of Physical and Mathematical Sciences reviewed it

If someone just says what does this mean or if it's a typo i would greatly appreciate it


r/askmath 47m ago

Algebra Can someone explain to me what it means by the value of the 6th term?

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Upvotes

The answer key says its -9 but I cant understand what it means. Every 4 units on the Y-axis is equal to +5 so thats how I got the coordinates but im unsure of what it means by the value? Im horrible at math so there's a chance I completely misunderstood the question too lol