Questions about studying mathematics without formal instruction.

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2
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3answers
23 views

Why $ (1- \sin \alpha + \cos \alpha)^2 = 2 (1 - \sin \alpha)(1+ \cos \alpha)$?

Why $ (1- \sin \alpha + \cos \alpha)^2 = 2 (1 - \sin \alpha)(1+ \cos \alpha)$? I am learning trigonometric identities one identity I have to proof is the next: $ (1- \sin \alpha + \cos \alpha)^2 = ...
1
vote
1answer
55 views

Typical material covered in Calculus 1 course?

I have a copy of Larson's Calculus: early transcendental functions, 2nd edition. I was wondering what material I would need to cover to have the equivalent of a Calculus 1 course at a University. I ...
0
votes
1answer
52 views

Have any one studied this binomial like coefficients before?

Note that the simillarities of following identities. $\dbinom{n}{r}=\dbinom{n}{n-r}$ $\dfrac{n}{n-r}\dbinom{n-r}{r}=\dfrac{n}{r}\dbinom{n-r-1}{r-1}$ $\dbinom{n}{r-1}+\dbinom{n}{r}=\dbinom{n+1}{r}$ ...
0
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2answers
33 views

Could anybody provide a more detailed explanation of a tangent equation in its general form?

In my textbook I'm currently at the topic of a tangent line to an ellipsis and hyperbola. And there I've encountered this statement: If a curve has an equation $$ y = f(x) $$ then an equation of a ...
0
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3answers
41 views

how to prove $ax + by = cx + dy \implies a = c, b = d$?

Actually the question is in the title. I just have saw such a method $$ ax + by = cx + dy \implies a = c, b = d $$ in my textbook, so I can assume it is true, but I'm very interested on proving ...
0
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2answers
34 views

If $X$ has CDF $F$, how can I find the CDF of $U= \max \{0,X \}$?

If $X$ has CDF $F$, how can I find the CDF of $U=\max\{0,X\}$? Obviously the suport of $U$ consists solely of nonnegative values. Am I right then in thinking that for $u=0, F_U (u)=F_X(0)$ and for ...
0
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0answers
25 views

Uniformly analytic functions

Consider the following definition: Let $\Omega$ be an open set of $\mathbb{R}_x^n$, $x = (x_1, ..., x_n)$. A $\mathcal{C}^{\infty}$-function $\varphi(x)$ on $\Omega$ is said to be uniformly analytic ...
3
votes
2answers
77 views

Intuition about Taking an Integral

My hope is to personally develop some further intuition for taking an integral (measuring the area under a curve). Consider a normal distribution and I need the area under the curve from $a$ to $b$. I ...
1
vote
5answers
57 views

Prove $\frac{\sin A}{\sec A+\tan A-1}+ \frac{\cos A}{\csc A+\cot A-1}=1$

$$\frac{\sin A}{\sec A+\tan A-1}+ \frac{\cos A}{\csc A+\cot A-1}=1$$ Prove that L.H.S.$=$R.H.S. This type of questions always creates problem when in right hand side some trigonometry function is ...
2
votes
1answer
56 views

Prove this result about construction of sets

In Enderton's book on Set Theory, the following problem is given after introducing the notion of sets as an infinite hierarchy (I hope this much explanation is sufficient; if not, please mention and ...
2
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5answers
100 views

Introduction and Prerequisites to Abstract Algebra

So I've seen similar questions asked, but none that really helped me out. I'm going to be a freshman in college next year, having already taken Multivariate Calculus and Elementary Linear Algebra. Of ...
1
vote
3answers
58 views

Transformation of two independent uniform random variables

Suppose $X,Y \sim \text{Uniform} \left(0,1 \right)$ are independent. Then I need to find the PDF for $W=X/Y$. By the CDF technique this is seen to be : $$F_W( w)=\int_{0}^1 \int_{0}^{wy} ...
3
votes
2answers
36 views

Favorite Textbooks for introducing a subject?

I'm interested in learning more about number theory, about fractal geometry, and about probability. Anyone have any good recommendations? I've taken calculus and statistics at university if that helps ...
2
votes
1answer
34 views

Confused about this set representation and conclusions

I'm pursuing Set Theory by Enderton and am having trouble understanding the following idea. Early in the book, the author constructs an "informal view" of sets, which he says he will refine further ...
1
vote
1answer
72 views

How do you self-study Functional Analysis?

It would be very handy to know about function spaces, distributions and Fourier stuff. It looks like Rudin's Functional Analysis covers these things, but I do not yet have the foundation for it. (see ...
1
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0answers
63 views

How long should you study Mathematics each day if you want to get into a graduate school? [closed]

I'm a university student (Junior now!) and I was wondering how many hours fellow undergraduates and graduate students study a day. I hear posts about how time doesn't really matter and that it's about ...
0
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0answers
59 views

Self-Contained Books / Series / Lectures for Comprehensive Introduction to College-Level Math for Someone with VERY Poor Math Foundation?

I've long been interested in various math related subjects (technology, philosophy, sciences, computer science, languages, etc.) without really invested time to actually any learn any of them. I ...
0
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2answers
27 views

Help with constructing power set

I' trying to construct the power set of $A = \{\phi, \{a\}\}$ and would appreciate some help. Now, the definition of a power set says that it's the set of all possible subsets of a given set. ...
6
votes
2answers
118 views

The best balance in studying Mathematics?

I'm a student studying Mathematics at a university level. I've completed Single Variable Calculus, Differential Equations, Multivariable Caculus, Real/Complex Analysis, and Linear Algebra and I've ...
2
votes
4answers
288 views

Should I read about Manifolds or Algebraic Topology?

I really enjoy doing maths and it fills quite a lot of my spare time. I'm starting my first year in the university on october and I probably won't have that much time for independent reading once ...
0
votes
1answer
33 views

The Landau symbol $\mathcal{o}$ as in Königsberger Analysis I

I am currently working on Chapter 14 - local approximations of function and Taylor polynomials - in Königsberger Analysis 1 Background: Königsberger introduced the Taylor Polynomial of order ...
3
votes
1answer
42 views

Start studying mathematical biology from basics

I am really passionate about theoretical and quantitative biology and I would like to build my future career around this topic. I've just got my bachelor's degree in biology (ecology) but scince ...
2
votes
1answer
36 views

Tutorial on Complex Networks

Can anyone advise mea nice and short tutorial about Complex Networks? I'm reading "Networks: An Introduction" from Mark Newman, and is a bit tedious... Thanks PS: There isn't a tag "complex networks" ...
0
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0answers
27 views

Most suitable book after Bergmann Logic Book

I'd like to know what the best book would be to pick up after this one would be. Essentially, it covers basic logical concepts (validity, soundness, consistency) and goes on to sentential and ...
0
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0answers
15 views

Volume of parallelepiped gets smaller when using projection vectors

Given a Euclidean Space R and a subspace R' (of dimension $\geq$m), consider vectors $x_1,...,x_m \in$**R**, and let $V[x_1,...,x_m]$ mean the volume of an m-dimensional parallelepiped formed by those ...
2
votes
3answers
85 views

Trouble with inequalities

I'm a 9th grade student, going into 10th grade. Math has always been a subject I enjoyed and excelled in. I'm writing a schoolboard-wide math contest next year in mid-February I believe. To prepare ...
4
votes
1answer
71 views

Riemann Sums as in Königsberger Analysis 1

Intro: I must take a small detour here which is only relevant if you do not know the book itself and care about my background. I am working with Königsberger Analysis I (can be found on Springerlink). ...
1
vote
0answers
29 views

Generator Matrix

I have a C in $F_2^6$ $(x_1,x_2,x_3,x_4) \to (x_1,x_2,x_3,x_4,x_1+x_2,x_3+x_4)$ for $x = (1,0,1,1)$ i get $c = (1,0,1,1,1,0)$ we know that $$c = G . x$$ G is the Generator Matrix in the solution ...
0
votes
3answers
51 views

Learning timetables

This is a basic question, but I am revisiting them due to some examinations I need to take that involves mathematics. I want to be nimble with mental arithmetic so have decided to go back and learn my ...
0
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1answer
27 views

Continuity of a map to a Frechet space

Let $(A,\| \cdot \|)$ be a normed space and $B$ be a Frechet space equipped with a family $\{ p_k \}_{k \in \mathbb{N}}$ of seminorms. Let $\phi: A \to B$ be a linear transformation satisfying the ...
5
votes
3answers
51 views

Area preserving transformation in a higher dimensional space is unitary.

In $\mathbb{R}^3$, a linear operator $Q:\mathbb{R}^3 \to \mathbb{R}^3$ preserves the area of parallelograms: that is, given $x,y\in \mathbb{R}^3$, the area of a parallelogram formed by $x$ and $y$ is ...
0
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1answer
14 views

quick question on measurability of random variables and what becoming a deterministic function means.

we stated a theorem in class: if X r.v. is $\sigma(Y)$ measurable then X is a function of Y, where $\sigma(Y)$ signifies the sigma algebra of Y. This is fine. The Professor sometimes states that X ...
0
votes
1answer
25 views

Logarithm with variable base

I am trying to define a function that maps polynomials in the form of $x^{3^n}$ to the value of $n$ in the polynomial, where $n\in{Z}$.* Is is valid to define this function as $log_{x^3}(u)$, where ...
1
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0answers
45 views

Soft question — I need books and exercise books that will be working on my fundamental skills.

I need help, urgently. I acquired a book called: Mathematics, Its Content, Method and Meaning. Now the problems is the book doesn't provide me with any exercises. I was searching for a book that would ...
2
votes
2answers
23 views

Probability of returning to a given state after n transitions-Markov chains

Let us denote $f_j^{(n)}$ denote the probability of the first return to state $j $after n transitions. Let $p_{jj}^{(n)}$ be the probability of returning to the state $j$ after $n$ transitions when ...
1
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1answer
17 views

Confusion with Bolyai-Gerwien theorem

The Bolyai-Gerwien theorem states: Given two polygons with the same area, it is possible to cut up one polygon into a finite number of smaller polygonal pieces and from those pieces assemble into ...
1
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1answer
15 views

Queuing theory-Multiple server (reducing simple recurrence formulas)

The equations given in 6.3 have been reduced which really eases the computation in further studies. But I tried to find the method of reducing these but I could not find a way at all. Any hints will ...
-1
votes
2answers
27 views

Prove this result about power sets [duplicate]

I have to prove this result: If $P$ be the power set, and $B$ and $C$ are two sets, then if $B \subseteq C$ prove that $P(B) \subseteq P(C)$. Now, it seems obvious to me that since all the ...
1
vote
1answer
71 views

Math self-study in the holidays

In the upcoming holidays, I have got 6 weeks free to learn some new math (I was thinking of calculus and linear algebra). It's useful for my high school math skills (I don't live in America, so my ...
0
votes
1answer
65 views

What is the metric spaces needed to motivate concepts of general topology?

I intend to start learning some topology on my own. I wonder How much metric spaces I should know in order to motivate the concepts of topology? I know it's possible to learn topology without any ...
0
votes
0answers
39 views

Can ergodic Markov chains be periodic?

I found a statement in one of my notes which said If a state is persistent, aperiodic and not null the it is said to be ergodic Is it necessary that it should be aperiodic? This statement ...
1
vote
1answer
23 views

Markov chains: An issue in classification of states

I recently came across a lemma which goes as follows. Suppose a Markov chain has N states. Let i and j be pair of states. Then j can be reached from i iff there is an integer $ 0 ≤n< N$ such ...
0
votes
2answers
50 views

Find the galois group of the polynomial when a root is given

If $\alpha$ is a root of a polynomial $f(x)=x^3 +x^2-4x+1$ then show that $2 - 2\alpha - \alpha^2$ is also a root of $f(x)$. Use this fact to compute the Galois group of the splitting field of $f(x)$ ...
2
votes
2answers
56 views

Intersection of ideals $I=(2x)$ and $J=(2x^2)$ of $\mathbb{Z}[2x,2x^2,2x^3,\dots]$ is not finitely generated.

Consider the subring $\mathbb{Z}[2x,2x^2,2x^3,\dots]\subset \mathbb{Z}[x]$. Then show that the intersection of ideals $I=(2x)$ and $J=(2x^2)$ of $\mathbb{Z}[2x,2x^2,2x^3,\dots]$ i.e., $I\cap ...
2
votes
8answers
707 views

What are the most important functions every mathematician should know? [closed]

I am an undergrad in math and was wondering, what are for you the most important functions every mathematician should know? At the moment I think ...
1
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4answers
45 views

A simple conditional probability problem

Assume that two fair dice are rolled one at a time. Given that the sum of the two numbers that occured was at least $7$, compute the probability that it was equal to $7$. I tried computing the ...
1
vote
2answers
32 views

Proof that the subset relation is reflexive and transitive

I'm teaching myself set theory, and I'm not sure how detailed I should be when asked to prove things. Here is my proof that $A\subseteq A$ (the subset relation is reflexive): $A \subseteq B$ iff ...
1
vote
1answer
31 views

Optimization with both equality and inequality constraints

I need to minimize the following quantity: $$\min x_1^{-1/n}- \left(1-x_2 \right)^{-1/n}$$ subject to: $1-x_1-x_2=\gamma$ and $0<x_1+x_2<1$ $\gamma$ being a constant. Had it been two ...
24
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8answers
2k views

Complex analysis is more “real” than real analysis

In physics, in the past, complex numbers were used only to remember or simplify formulas and computations. But after the birth of quantum physics, they found that a thing as real as "matter" itself ...
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2answers
24 views

law of total probability and conditiona probability exercise.

Exercise: Let $X$ be an uniform discrete r.v. with four possible values: 1, 2, 3, 4. Let $Y$ be an exponential variable whose parameter is the value taken by $X$. So, if $X = 3$, $Y$ is Exp (3). ...