MTHS 212 LINEÊRE ALGEBRA LINEAR ALGEBRA Wat is lineêre algebra? What is linear algebra? The branch of mathematics that deals with the theory of systems of linear equations, matrices, vector spaces, determinants, and linear transformations. The American Heritage® Dictionary of the English Language, Fourth Edition copyright ©2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. LINEÊRE VERGELYKINGS LINEAR EQUATIONS Stelsels lineêre vergelykings Systems of linear equations Uitkomste / Outcomes Aangevulde matrikse / Augmented matrices Ekwivalente stelsels / Equivalent systems Elementêre rybewerkings/ Elementary row operations Herleiding na rytrapvorm / Transforming to row echelon form Bepaal aantal oplossings van stelsels sowel as oplossings self / Determine number of solutions as well as solutions themselves. Toepassings / Applications Definisie / Definition ‘n Lineêre vergelyking in die veranderlikes A linear equation in the variables x1 ,, xn is ‘n vergelyking wat geskryf kan word in die form is an equation that can be written in the form a1 x1 + a2 x2 + + an xn = b waar b en die koëffisiënte a1 ,, an where b and the coefficients reële of komplekse getalle is wat gewoonlik bekend is. are real or complex numbers that are usually known in advance. Nog definisies / More definitions ‘n Stelsel lineêre vergelykings (of ‘n lineêre stelsel) is ‘n versameling van een of meer lineêre vergelykings in dieselfde veranderlikes, byvoorbeeld 𝑥𝑥1, … . , 𝑥𝑥𝑛𝑛. A system of linear equations (or a linear system) is a collection of one or more linear equations involving the same variables — say, 𝑥𝑥1, … . , 𝑥𝑥𝑛𝑛. MTI-IS �11 I-I { Vct:Jrkeld 1 / E. 'K.avviple J J �J -+ X. o+/or X.1 -t" == 3 cl.x.. '2- -= 3 R � u ;i: lj.-i CJ= -fx_ � 1) ; � d'e fl I crf J{C-t k._ Liv-iet:r 9rap � ;"'\ -tL-ie f lqv,e_ o�be.l:..et'\d-esJ/ O�e era:hOV11 3 lh'l tno,JVl.f : �x_ + � + 3-=2. = of /c,r :2.. :x., -t- X i. -+ s X -1 6 'X-J b Stekek: /�sle""'s ;2 "e3eb8 GrC¾-Res ,/ Crcy,'1:co. I .· X2. :x ,i ;;)_ 011'\bet-e.,,des II ;)_ erqfiov1S vigs � x., -t- X 7- :::: -3 V l<=il:: iV) 3-d;,,.,., ru;""'� Pfa�e i r\ �-cl-, srce 1 .) Uo/l�Yl,f ;i ·r:tl 'j VJe ;/) I':) fctl:vfc.c lc. :t /,.-,ear 3�fhs ;,. f ( x, - x. 2.- = O 3 v'$ls J 3 onkl::e----deJ / 3 e'f,!'<c.f-io.-1 S1 3 un L.-.owns : x, - :x� ---t- X .1 ==- ( 3 f f e � i 3 -o(/N'l o/'7lq_ Ce... Qvie_ � X, -t )(_ ?... -+ 3 ::( "! =:- -( x, + .:t � ,.... - '.)(.3 -=- 2 Cf,,-, 6 vIC< t t VJ e.. i..., 3 -cir� r-u,·N\ le . Nog definisies / More definitions ‘n Oplossing van die stelsel is ‘n lys (𝑠𝑠1, 𝑠𝑠2, … , 𝑠𝑠𝑛𝑛) van getalle wat elke vergelyking ‘n waar bewering maak as die waardes 𝑠𝑠1, … , 𝑠𝑠𝑛𝑛 vervang word in 𝑥𝑥1, … , 𝑥𝑥𝑛𝑛. A solution of the system is a list (𝑠𝑠1, 𝑠𝑠2, … , 𝑠𝑠𝑛𝑛) of numbers that makes each equation a true statement when the values 𝑠𝑠1, … , 𝑠𝑠𝑛𝑛 are substituted for 𝑥𝑥1, … , 𝑥𝑥𝑛𝑛, respectively. Nog definisies / More definitions Die versameling van alle moontlike oplossings word die oplossingsversameling van die lineêre stelsel genoem. The set of all possible solutions is called the solution set of the linear system. Twee lineêre stelsels word ekwivalent genoem as hulle dieselfde oplossingsversameling het. Two linear systems are called equivalent if they have the same solution set. Grafiese interpretasie – 2 vgls, 2 onbekendes Graphical interpretation – 2 eqs, 2 unknowns Geen oplossing No solution Unieke oplossing Unique solution Oneindig veel oplossings / Infinitely many solutions Grafiese interpretasie – 2 of 3 vgls, 2 of 3 onbekendes Graphical interpretation – 2 or 3 eqs, 2 or 3 unknowns Verklaring van tipes op vorige skyfie Explanation of types on previous slide A. B. C. D. E. F. 3 vlakke wat sny in een punt (unieke oplossing) 3 planes intersecting in a single point. 3 vlakke wat sny in 'n lyn (oneindig veel oplossings) 3 planes intersecting in a single point. 3 nie-ewewydige vlakke met geen gemeenskaplike snypunte nie. 3 nonparallel planes with no common points of intersection. 3 vlakke wat saamval (oneindig veel oplossings vir stelsel) 3 planes coinciding (infinitely many solutions for system) 3 vlakke, 2 ewewydig en derde een nie-ewewydig – geen gemeenskaplike snypunte nie (geen oplossing nie) 3 planes, 2 parallel and third nonparallel – no common points (no sol) 3 ewewydige vlakke nie (geen oplossing nie) 3 parallel planes (no solution) Verklaring van tipes op vorige skyfie (vervolg) Explanation of types on previous slide (continued) G. H. I. J. K. L. Twee ewewydige vlakke (of 3, waarvan 2 saamval – geen oplossing nie) 2 parallel planes (or 3, of which 2 coincide – no solution) Twee lyne wat sny in een punt (unieke oplossing) Two lines intersection in one point (unique solution) 3 lyne, 2 ewewydig en derde nie-ewewydig (geen oplossing nie) 3 lines, 2 parallel and the third nonparallel (no solution) 2 ewewydige lyne (of 3 lyne, waarvan 2 saamval – geen oplossing nie) 2 parallel lines (or 3 lines, of which 2 coincide – no solution) 3 nie-ewewydige lyne wat sny in 'n enkele punt (unieke oplossing) 3 nonparallel lines intersection in a single point (unique solution) 2 of meer lyne wat saamval (oneindig veel oplossings) 2 or more lines coinciding (infinitely many solutions) Verklaring van tipes op vorige skyfie (vervolg) Explanation of types on previous slide (continued) M. 2 vlakke wat sny in 'n lyn (oneindig veel oplossings) N. O. 2 planes intersection in a line (infinitely many solutions) 3 ewewydige lyne (geen oplossings) 3 parallel lines (no solutions) 3 nie-ewewydige lyne met geen gemeenskaplike snypunt nie (geen oplossing nie) 3 nonparallel lines with no common point of intersection (no solution) Nog definisies / More definitions ‘n Stelsel lineêre vgls het / A system of lin. eqs has 1. geen oplossing nie, of / no solution, or 2. presies een oplossing /exactly one solution, or 3. oneindigveel opl. / infinitely many solutions. Ons sê ‘n stelsel lin vgls is oplosbaar of konsistent as dit een of oneindigveel opl het en onoplosbaar of inkonsistent as dit geen opl het. A system of linear equations is said to be consistent if it has either one solution or infinitely many solutions and inconsistent if it has no solution. Afspraak / Agreement Om stelsels vergelykings op te los, skryf ons hulle in aangevulde matriksvorm, byvoorbeeld ons skryf / To solve systems of equations, we write them in augmented matrix form, for example we write as Strategie / Strategy Ons vervang ‘n stelsel met ‘n ekwivalente eenvoudiger stelsel deur elementêre rybewerkings uit te voer. We replace a system with an equivalent simpler system by means of elementary row operations. ELEMENTÊRE RYBEWERKINGS ELEMENTARY ROW OPERATIONS Ons kry die volgende elementêre rybewerkings: Elementary row operations include the following: 1. (Vervanging) Vervang een ry met die som van homself en ‘n veelvoud van ‘n ander ry. (Replacement) Replace one row by the sum of itself and a multiple of another row. 2. (Ruiling) Ruil twee rye (Interchange) Interchange two rows. 3. (Skalering) Vermenigvuldig al die inskrywings in ‘n ry met ‘n nie-nul konstante. (Scaling) Multiply all entries in a row by a nonzero constant. Slide 1.1- 18 © 2012 Pearson Education, Inc. Definisie / Definition Twee matrikse word ry-ekwivalent genoem as daar ‘n ry van elementêre rybewerkings is wat een matriks verander in die ander. Two matrices are called row equivalent if there is a sequence of elementary row operations that transforms one matrix into the other.