What is Algebra: Definition and 999 Discussions

Algebra (from Arabic: الجبر‎, romanized: al-jabr, lit. 'reunion of broken parts, bonesetting') is one of the broad areas of mathematics, together with number theory, geometry and analysis. In its most general form, algebra is the study of mathematical symbols and the rules for manipulating these symbols; it is a unifying thread of almost all of mathematics. It includes everything from elementary equation solving to the study of abstractions such as groups, rings, and fields. The more basic parts of algebra are called elementary algebra; the more abstract parts are called abstract algebra or modern algebra. Elementary algebra is generally considered to be essential for any study of mathematics, science, or engineering, as well as such applications as medicine and economics. Abstract algebra is a major area in advanced mathematics, studied primarily by professional mathematicians.
Elementary algebra differs from arithmetic in the use of abstractions, such as using letters to stand for numbers that are either unknown or allowed to take on many values. For example, in



x
+
2
=
5


{\displaystyle x+2=5}
the letter



x


{\displaystyle x}
is an unknown, but applying additive inverses can reveal its value:



x
=
3


{\displaystyle x=3}
. Algebra gives methods for writing formulas and solving equations that are much clearer and easier than the older method of writing everything out in words.
The word algebra is also used in certain specialized ways. A special kind of mathematical object in abstract algebra is called an "algebra", and the word is used, for example, in the phrases linear algebra and algebraic topology.
A mathematician who does research in algebra is called an algebraist.

View More On Wikipedia.org
  1. rpthomps

    Heisenberg's Uncertainty Principle using Linear Algebra

    I am working through linear algebra from MITs MOOC online courses. One of the question refers to the uncertainty principle. It states: AB-BA=I can happen for infinite matrices with A A=A^{ T }\\ and\\ B=-B^{ T }\\ Then\\ x^{ T }x=x^{ T }ABx-x^{ T }BAx\le 2\parallel Ax\parallel \parallel...
  2. D

    Partial Fractions: Why Does (x+1)2(2x+1) Need 3 Terms?

    Why, when a fraction has repeated linear terms in its denominator e.g. (11x2+14x+5)/[(x+1)2(2x+1)] does it have to be split into three partial fractions, A/(x+1) + B/(x+1)2 + C/(2x+1)? When my first saw this example, my initial reaction was to split it into A/(x+1)2 +B/(2x+1), but after working...
  3. Ganesh Ujwal

    MHB What Is the Maximum Size of Polynomial Subspaces in Finite Fields?

    Let $\mathbb F_q$ be a finite field and let $e, k$ be positive integers with $k \leq e < q-1$. Define $T_e$ to be the set $$T_e:=\left\{p(x) \in \mathbb F_q[x] \;|\; \deg p =e \;, lc(p)=1, \; p(x)|x^{q-1}-1 \right\}. $$ I would like to find the value $$ M(e,k,q):=\max\left\{ | W \cap T_e|...
  4. B

    Linear Algebra Seeking Advice on Linear Algebra Textbooks Selection

    Dear Physics Forum personnel, I am a college sophomore with double majors in mathematics and microbiology. I apologize for this interruption but I wrote this email to seek your advice and recommendation on linear algebra textbook. I will be taking the "theoretical, proof-based" introductory...
  5. P

    MHB Solving Algebra Problems: 2.(c,i),(c,ii),(c,iii) Exam Paper

    Hiya. Im having problems with Questions 2.(c,i),(c,ii) and (c,iii) question on this past exam paper. http://www.nzqa.govt.nz/nqfdocs/ncea-resource/exams/2014/91261-exm-2014.pdfCan someone check my answers and explain the questions where I face planted? Thanks! 2. (c,i). I got h/(rx-t) = x, I...
  6. PcumP_Ravenclaw

    Understanding the fundamental theorem of algebra

    Dear all, I am trying to understand the fundamental theorem of algebra from the text (Alan F. Beardon, Algebra and Geometry) attached in this post. I have understood till the first two attachments and my question is from the 3rd attachment onwards. I will briefly describe what...
  7. binbagsss

    GR: Quick Q, conservation energy, stuck on algebra

    I'm stuck on deriving the follow. Context: FRW Metric, dust dominated universe, use of conservation of energy-momentum tensor. I'll now state all the equations I can see are relevant. (But just in case the source is http://arxiv.org/pdf/gr-qc/9712019.pdf and it's eq 8.43). ## \frac{d}{dt}(\rho...
  8. J

    Calculating Probabilities in a Double-Elimination Tournament

    Homework Statement In Game 6 of a 6-team double-elimination tournament, Team 1, the top-ranked team, faces the loser of a previous game involving Team 2, the second-ranked team, against one of either Team 3, the third-ranked team or Team 6, the sixth-ranked team. This exercise tests the limits...
  9. P

    Rigorous Precalculus and Calculus Textbooks + Intro to Linear Algebra

    I am currently studying A level Further Pure Mathematics, and I will be joining university next year. I want to brush up on precalculus (algebra, trigonometry, geometry) and calculus (differential, integral [single variable]), except that this time I need a more rigorous treatment of those...
  10. Porthos

    Second Course in Linear Algebra

    I am planning my courses for next semester, and I am unsure of which direction to go in with linear algebra. I have already taken the following course: Linear Algebra I Properties and applications of vectors; matrix algebra; solving systems of linear equations; determinants; vector spaces...
  11. A

    Converting single integral to double integral

    Homework Statement Please refer to : http://math.stackexchange.com/questions/1068948/how-to-prove-that-int-0-infty-sinx-arctan-frac1x-mathrm-dx-fra/1069065#1069065 The answer by @venus. What is the procedure in converting that single integral, dividing it into parts, and making it a double...
  12. B

    Are pq and qp always 3-cycles?

    Homework Statement In the text, the products pq and qp of the permutations (2 3 4) and (1 3 5) were seen to be different. However, both products turned out to be 3-cycles. Is this an accident? Homework Equations p=(3 4 1)(2 5) q=(1 4 5 2) where p and q are permutations The Attempt at a...
  13. B

    How Can You Solve the Algebraic Equation √((a+b) + 2 √ab) = √a + √b?

    How to find ##\sqrt{(a+b) + 2 \sqrt{ab}} = \sqrt{a} + \sqrt{b}## ?
  14. SalfordPhysics

    How is the error in the gradient calculated?

    Homework Statement A series of 5 measurements of Y are recorded with increasing X. (i.e. gradient has units Y/X) The error in measurement of Y is ±0.05 The error in measurement of X is ±0.005. How is the error in the gradient calculated? Homework Equations - measurements[/B] Y | X...
  15. K

    Little question about eigenvalues

    Hey there, I'm thinking about if one of the eigenvalues is zero (means determinant is 0. right?) So, is there any possibility to non-zero eigenvalue also exists?
  16. D

    Master Boolean's Algebra with SOP: Simplifying F(X, Y) to XY' + XY

    Can someone please explain why the F( X, Y ) is XY' + XY ? IMO , it is X'Y' + X'Y +XY' +XY ... or the author simplified it to become XY' + XY ? how to simplify it?
  17. PsychonautQQ

    Linear Algebra Dual Space

    Homework Statement Let Hom(V,W) be the set of linear transformations from V to W. Define addition on Hom(V,W) by (f + g)(v) = f(v) + g(v) and scalar multiplication by (af)(v) = af(v. If V is a vector space over a field K, define V* = Hom(V,K). This is called the dual space of V. If...
  18. T

    Lie Algebra of Lorentz Group: Weird Notation?

    In Srednicki's text on quantum field theory, he has a chapter on quantum Lorentz invariance. He presents the commutation relations between the generators of the Lorentz group (equation 2.16) as follows: $$[M^{\mu\nu},M^{\rho\sigma}] =...
  19. M

    Skier traveling uphill with and without friction

    Homework Statement If the coefficient of kinetic friction in the previous problem was actually 0.11 and the slope 30 degrees, to the nearest meter how far up the hill does he go? **the problem prior was: A skier traveling at 31.9 m/s encounters a 12 degree slope. If you could ignore friction...
  20. Kac28891

    I want to self teach College Algebra but I don't know how?

    I was enrolled in College Algebra for this upcoming winter because the hours will overlap with the class that I enrolled for spring. The reason why I want to learn this, is to refresh my Algebra skills, since I forgot most of it (I only remember matrices, radicals and identities). The purpose...
  21. K

    Is it possible to determine a basis for non-subspace spaces?

    The title may seem a little confusing and possibly stupid :D What I mean is like a plane doesn't go through the origin? Can we describe a basis for this? If so, how?
  22. T

    MHB Why is my teacher calling 2m+(50s)(0.5m/s) pure piffle?

    2m+(50s)(0.5m/s) = 2m + 25m/{s}^{2} = Not possible My teacher keeps saying this is pure piffle and shaking his head. Can someone please explain this to me?
  23. T

    Abstract Linear Algebra: Eigenvalues & Eigenvectors

    Homework Statement Let V be a finite dimensional vector space over ℂ . Show that any linear transformation T:V→V has at least one eigenvalue λ and an associated eigenvector v. Homework EquationsThe Attempt at a Solution Hey everyone I've been doing sample questions in the build up to an exam...
  24. T

    Unique Vector a in V such that L(x) = <a,x>

    Homework Statement Let V be a finite-dimensional real vector space with inner product <⋅,⋅> and L: V → R a linear transformation. Show that there exists a unique vector a ∈ V such that L(x) = <a,x>. Homework Equations Hey everyone, so I'm a physics student who had to choose a few electives in...
  25. J

    Should I Take Algebra 4 for My Mathematics Degree?

    I'm a second year student at university studying mathematics. I'm having troubles deciding between a few modules and I hope you can help. http://www.ucl.ac.uk/maths/courses/undergraduates is where all the modules are, please take a look at "Honours Year 2" I get to choose four modules, and so...
  26. TheBiologist

    Linear and Abstract Algebra: What Is It?

    Not quite sure, could someone kindly explain the concept of the topic to me? Thanks, it really means a lot. :)
  27. M

    Vector Calculus, Multivariable Calculus, Linear Algebra

    I am in Calculus BC in high school right now and I am really enjoying it and have finished all of the material for the year and I have heard different things about what class comes after Calculus BC (I believe BC is equivalent to Calc 1 & 2 in college). I have heard the next class, aka Calc 3...
  28. FuturePhysicist

    Teaching myself geometry, algebra 2, and calculus.

    Hey, I am a freshman in High School and I have a very superior IQ but I am in normal classes. This is due to ADHD and I used to be lazy in school. Anyways, algebra 1 is VERY boring. I want to teach myself geometry, algebra 2, Pre Cal, and Calculus because I love math. Also I feel like it will...
  29. M

    Interpolation and linear algebra

    Homework Statement As a string in my program. Homework Equations Solving a system with the forward phase of row echelon reduction and a consecutive back substitution. All done by numpy here. (The book suggested MATLAB, etc). The Attempt at a Solution import numpy """ In a wind tunnel...
  30. Heisenberg1993

    Basic Questions in linear algebra and group theory

    1- How can infer from the determinant of the matrix if the latter is real or complex? 2- Can we have tensors in an N-dimensional space with indices bigger than N?
  31. A

    Talking points in Commutative Algebra, please

    < Mentor Note -- thread moved to HH from the technical math forums > My final assignment in graduate algebra is to write an essay about the relationship among the subjects we have learned so far this semester: (1) Module (2) The Field of Fractions of an Integral Domain (3) Integrality (4)...
  32. S

    Math Elective Help: Abstract Algebra, Theory of Numbers, or Symbolic Logic?

    Hello, I'm debating between taking either abstract algebra, theory of numbers, or intermediate symbolic logic as a math elective. Does anyone have any idea which would make my life easier?
  33. P

    Algebra of pulley-mass energy equation

    Homework Statement [/B] A 0.20-kg block and a 0.25-kg block are connected to each other by a string draped over a pulley that is a solid disc of inertia 0.50 kg and radius 0.10 m. When released, the 0.25-kg block is 0.30 m off the ground. What speed does this block have when it hits the ground...
  34. TheExibo

    Solve for X: 4*(5^x)-3(0.4^2x)=11 | Quick Algebra Homework

    Homework Statement 4*(5^x)-3(0.4^2x)=11 In case it doesn't make sense, in the attempted solution it's written out better Homework EquationsThe Attempt at a Solution http://imgur.com/SnpFQZV Thanks!
  35. J

    Inequalities in Force of Gravitation between Three Bodies

    Homework Statement Given that the force of gravitation between Planet A (the one in the left side of the drawing), Fa=3000/da2 and the force of gravitation between Planet B and the rocket, Fb= 6000/ db2. Assuming that the three bodies involved is in stationary. What are the distances (ranges)...
  36. M

    Do I Need All Three Math Textbooks by Ron Larson?

    https://www.amazon.com/dp/1133949010/?tag=pfamazon01-20 https://www.amazon.com/dp/1285057090/?tag=pfamazon01-20 https://www.amazon.com/dp/1133959741/?tag=pfamazon01-20 So I'm planning on buying the books in the links above (Algebra and trig, precalc and calc by Ron Larson), but as they are...
  37. G

    Solutions to first order equation with Clifford algebra elements

    In the same way one can show that \nabla^{2}\theta=0 has only one smooth solution, namely \theta=0, I would like to show that \gamma^{i}\partial_{i}\epsilon=0 has only one smooth solution, where \gamma^{i} is a Dirac gamma matrix (or an element of the Clifford algebra), and \epsilon is a...
  38. C

    Solving Algebraic Expressions with Potens Rules | Quick Homework Question

    Homework Statement I stated this as a small attached photo, since i still need to learn to write in latex (see photo) Homework Equations How do you transform the first expression into the next expression (on photo)? The Attempt at a Solution [/B]I tried various manipulations with potens...
  39. E

    Can someone understand this passage of Linear Algebra?

    Homework Statement Hello there everybody! I'm reading a Linear Algebra textbook, specifically on LTV systems solutions. I'm trying to redo this example from the book: Homework Equations But I couldn't understand the passage: The Attempt at a Solution I mean. x1(0) = 1 and x2(0) = 0? I...
  40. I

    Algebra help with complex numbers

    Homework Statement goal: solve for t; all else are constants $$cos(\omega t)=1-e^{-(\frac{t}{RC})}$$Homework Equations noneThe Attempt at a Solution i turned the cos to complex notation & rearranged $$e^{i\omega t}+e^{-(\frac{t}{RC})}=1$$ $$ln(e^{i\omega t}+e^{-(\frac{t}{RC})})=0$$ and i...
  41. D

    Quaternions and Clifford Algebra problems

    Hello, I have some problems with understanding some concepts in Quaternions and Clifford Algebra. For example, where can I learn the basic construcion of Clifford Algebra? I'm listing the equalities I did not understand and I appreciate it if you can help me with understanding these : Homework...
  42. E

    Linear Algebra Axler vs Shilov?

    Hi all, So I'm going to have my first exposure to linear algebra and I've completed Calc 1 and 2. I've seen Axler and Shilov numerous times and I'm having a hard time choosing it. Here's my syllabus for my Linear Algebra Course. Matrices, Gauss reduction, invertibility. Vector spaces, linear...
  43. E

    How Much Force is Needed to Move a Wire with Soapy Solution?

    1. Calculate the force needed to move the wire in the figure (Figure 1) if it holds a soapy solution (surface tension is 0.025 N/m) and the wire is 16.0 cm long. Express your answer to two significant figures and include the appropriate units. 2. γ(surface tension) = F (force) / l (length)...
  44. HaLAA

    Linear Algebra: linear transformation

    Homework Statement let A be the matrix corresponding to the linear transformation from R^3 to R^3 that is rotation of 90 degrees about the x-axis Homework Equations find the matrix A The Attempt at a Solution I got stuck on rotating z component. I tried T([e1,e2,e3])=[0 -1 0]...
  45. C

    Impedance network and complex algebra

    Homework Statement This is one part of a wider question, I'm only posting the part I'm having trouble with. $$ \begin{align} \text{Given an impedance network } B &= \frac{Z_1 \parallel Z_3}{Z_2 + Z_1 \parallel Z_3} \\ \text{show that: } \frac{1}{B} &= 1 + \frac{R_2}{R_1} + j\frac{\omega CR_2}{1...
  46. N

    Geometric Description of Subspace Spanned by Set S

    Homework Statement Determine whether the set S spans R3. If the set does not span R3, then give a geometric description of the subspace that it does span S = [ (2,0,3) , (2,0,-1) , (6,0,5) , (4,0,6) ] Homework EquationsThe Attempt at a Solution I know S does not span R3 because the system of...
  47. A

    What is the derivation and meaning behind the SO(2,1) invariance algebra?

    Hello, Please excuse me about my ignorance. I would like to know how SO(2,1) Lie algebra, is derived from operators and commutators. I have some notes, that the Lie algebra of SO(2,1) is derived from: [D,H]=-iH [K,D]=-iK [H,K]=2iD where D, H, and K are the "generators". I have no clue what does...
  48. G

    How essential is non-commutative algebra in theoretical physics?

    For next term, I was wondering if I should take a course in non-commutative algebra. As of now, I'm focusing on mathematical physics, specifically on the mathematical side of string theory; mirror symmetry and field theories. I know that commutative algebra as well as algebraic geometry are...
  49. JonnyMaddox

    Lie Groups, Lie Algebra and Vectorfields

    Hi I'm learning about Lie Groups to understand gauge theory (in the principal bundle context) and I'm having trouble with some concepts. Now let a and g be elements of a Lie group G, the left translation L_{a}: G \rightarrow G of g by a are defined by : L_{a}g=ag which induces a map L_{a*}...
  50. K

    Need help with some linear algebra questions

    Okay, long story short, my mom could not work because of an illness so me and and family all had to chip in so fulfill the mortgage payment on our home. I worked two jobs and am a full-time student. I've been studying as much as I possibly can and may have to temporarily restrain from spring...
Back
Top