Chapter 01: System of linear equation and matrix V1 — Transcript
Full transcript
- 0:00foreign
- 0:00[Music]
- 0:07today I will introduce you about linear
- 0:11zebra
- 0:12so in linear algebra we have more about
- 0:15relation in here
- 0:17the first of our relation in linear
- 0:20algebra I talk about the system of
- 0:22linear equation and Matrix Matrix so the
- 0:25first
- 0:26today I will introduce you about the
- 0:30system of linear equation so what is
- 0:32linear equation before you know about
- 0:34the system or linear equation you should
- 0:36we know about the linear equation
- 0:38I think you know me already uh
- 0:42the the old generation but you are the
- 0:46new generation of uh ninth generation I
- 0:49think
- 0:51maybe you know my name my name is and I
- 0:54do that in here and I am a lecturer at
- 0:57cadt also uh mathematic lecture
- 1:02so now I will uh introduce you or I will
- 1:06teach you about deletion of system of
- 1:09linear equation
- 1:10so now uh linear equation the first
- 1:14point we talk about the system of linear
- 1:17equation and Matrix
- 1:19and the next
- 1:21we talk about the ghost elimination so
- 1:24what is the ghost elimination
- 1:27and the next
- 1:30we talk about the linear equation
- 1:33we talk about the linear system equation
- 1:37we talk about the elementary row
- 1:39operation
- 1:41we talk about the ghost scene
- 1:43elimination so our main point in this
- 1:46lesson we talk about the gaussian
- 1:48elimination
- 1:49how can you solve the system of linear
- 1:52equation by gaussian elimination
- 1:55and this is our expect our output
- 1:59after you finish this lesson you can get
- 2:02knowledge of system of linear equation
- 2:05understanding and soul sum of system of
- 2:09linear equation
- 2:11and create to solve the system create to
- 2:14solar system it means that you can
- 2:16make your xxi you can make more exercise
- 2:20by yourself and to solve in your group
- 2:22or in virtually for your uh
- 2:27learning
- 2:28so our learning outcome objective in
- 2:32distillation you will be able to study
- 2:34about ocean elimination
- 2:36linear equation
- 2:38system of linear equation
- 2:40Elementary row operation and gaussian
- 2:43elimination so the first we talk about
- 2:46the system of equation
- 2:48H geometry
- 2:51our outcome related to a type of
- 2:54solution of a system of two or three
- 2:57variables to the intersection of line in
- 3:01a plane the intersection applied in this
- 3:05three space
- 3:07it means that we talk about in our space
- 3:10and three dimension you may remember
- 3:13this is uh the the system of
- 3:18this is not system of linear equation
- 3:20this is only uh
- 3:23linear equation so you should be you
- 3:26know linear equation and sometimes you
- 3:28call this is the line equation also
- 3:31so linear equation is the equation that
- 3:34have
- 3:35uh two water board or three bar wall but
- 3:39have only
- 3:40power one the degree is one degree of
- 3:44our variable is one so this is we call
- 3:47linear equation
- 3:48so equation
- 3:50uh we talk about we think about the
- 3:54right hand side and the left hand side
- 3:56so right hand side equal to left hand
- 3:58side and the vertical is power one so we
- 4:01call this this linear equation like I
- 4:04cycle for you on 2x plus 3y equal to six
- 4:08so this is recall about the uh
- 4:13linear equation so you can solve linear
- 4:17equation from Grade 9 grade 10 grade 11
- 4:21and grade 12 also so how can you solve
- 4:24about this uh linear equation when you
- 4:27want to find X
- 4:29you should be give the value of y and
- 4:33when you want to find y you will give
- 4:34the value of x also or example if you
- 4:38want to X Plus y
- 4:41example 2x plus y
- 4:44to X Plus
- 4:463y equal to 6 so you can give this one
- 4:50example you give Y is equal to zero and
- 4:54X is equal to three so you got three
- 4:58multiplied by two multiplied by three
- 5:01and plus three multiplied by zero is
- 5:04equal to six so this is true
- 5:07or sometimes you can take uh
- 5:112X and write 2x plus 3y equal to 6 4 to
- 5:176 and you can give this one is like a
- 5:21uh
- 5:22I can give this one is uh zero two
- 5:27multiplied by zero and plus 3 multiplied
- 5:31by two is equal to six also
- 5:34so you have more why this is you have
- 5:36more about the solution in some time in
- 5:40uh integer number number and sometime in
- 5:43real number also example is this I give
- 5:46you about this value this is only about
- 5:50uh
- 5:51integer number but in real number
- 5:54example I give two to X
- 5:58plus 3y
- 6:00equal to 6 equal to 6. so it means that
- 6:04in here
- 6:06I can
- 6:07give more about the value of X and Y X
- 6:12and Y example I give uh
- 6:16two
- 6:18multiplied by 1 and plus 3 multiplied by
- 6:23uh
- 6:28like six multiplied by 6 this is equal
- 6:32to uh
- 6:3420.
- 6:36equal to 20
- 6:38but our example this is only equal to 6.
- 6:42so how can you do this one to B6 so this
- 6:46is 18.
- 6:48this is 18. so x 10 plus 2 equal to 6 it
- 6:53means 18 plus 2
- 6:56become too sick so extinct how can you
- 6:58divide about extinct in here
- 7:00you know so there are many of our
- 7:04solution in uh
- 7:07linear equation
- 7:09because linear equation this is the line
- 7:12example I have this
- 7:14graph
- 7:16y prime or Y and X Prime o x so example
- 7:21this is a line
- 7:23this is a line so the intersection
- 7:25between X and Y
- 7:28between X and Y between X and Y between
- 7:32X and Y
- 7:33uh between X and Y
- 7:36the intersection between X and Y this is
- 7:38about like my point over here
- 7:46this is the solution of our equation
- 7:50so please remember that linear equation
- 7:54have more solution in here
- 7:56and the next point I will show you how
- 7:59to solve a linear equation in
- 8:03integer number
- 8:04integer number or in real number or in
- 8:08natural number how can you solve this
- 8:10equation and I will tell you more about
- 8:13more deeply about this uh solving of
- 8:17linear equation in the next point
- 8:20and let's start when we look to the
- 8:23intersection of the line
- 8:25so this is the first graph which I draw
- 8:29for you this one it means that we have
- 8:32about the line
- 8:34this is line one and this is line line
- 8:37two so this point this is the
- 8:40intersection of line one and line two
- 8:43you think line one and line two have
- 8:46only one intersection here in the
- 8:49section here so line one and line two it
- 8:52means that
- 8:54uh this is about the system of linear
- 8:57equation example this is line one
- 9:01and this is line two
- 9:04so line one in line two we have
- 9:06intersection one like a
- 9:09X row and y y zero so our system of
- 9:13linear equation have one solution
- 9:16so I I right here this is have only one
- 9:20solo solution because the intersection
- 9:22of line one and line two have only one
- 9:26point if have only one point it means
- 9:29that this equation or the system linear
- 9:32equation have only one slow solution and
- 9:36now you go to the next
- 9:38this is the next graph
- 9:41in a graph the next graph you see about
- 9:44the line one I
- 9:46let the red line is line one and the
- 9:49blue is the line two
- 9:51so you think line one and line two this
- 9:54is not intersection just on
- 9:57parallelization Parallel so a parallel
- 10:00so line one and line two cannot be
- 10:03intersection
- 10:04if cannot be except intersection line
- 10:07one and line two it does not meet each
- 10:10other
- 10:11when Line 1 and line two is parallel or
- 10:14not meet each other so our system of
- 10:17linear equation have no solution
- 10:19example if I get X plus 3
- 10:23plus 2y equal to Y and X
- 10:29Plus
- 10:30uh
- 10:33minus minus I put minus 2
- 10:37y equal to 9. this is on the example
- 10:42so if I draw about
- 10:45the graph
- 10:47example this is the graph and this is
- 10:50the line of
- 10:51this one and this is two so one and two
- 10:55so one and two cannot intersection so
- 10:58our system of linear equation cannot be
- 11:01cannot be have solution or we can say
- 11:05this is no true no solution and now you
- 11:09go to the graph three in graph three
- 11:12it means that you have you see only one
- 11:15line so if you draw example 2X
- 11:22plus 3y this is equal to
- 11:25uh six this is on the example I write
- 11:28for x and plus 6 y equal to 12.
- 11:33so if we know about the system of linear
- 11:37equation it means that the first
- 11:40the first equation
- 11:42is 2x plus 3y equals 6. and the second
- 11:48equation is 4X plus 6y equal to 12.
- 11:53equal to 12 in here
- 11:55so you think about the
- 11:58equation one equation one is 2X
- 12:02plus 3y equal to 6.
- 12:05and equation two
- 12:07equation two is for x
- 12:10plus six y equal to 12 and you can
- 12:15divide by two you can divide by two and
- 12:18divide by 2 you have 2X
- 12:20plus 3y equal to 6. so equation two and
- 12:25one
- 12:26equation 2 and 1 is the same
- 12:29when equation 2 and 1 is equal each
- 12:33other it means that this line is redone
- 12:36or this line is on the sample position
- 12:39like you see about this line the red
- 12:42line this is only one one line so if
- 12:45only one line you want to find about the
- 12:48solution it means that intersection
- 12:51between X and Y
- 12:53intersection between X and Y
- 12:56intersection between X and Y
- 12:58intersection between y this is
- 13:02the solution of this equation so have
- 13:05more
- 13:05more about
- 13:07intersection between x and x and y
- 13:11so
- 13:12in this graph in this graph it means
- 13:16that our solution
- 13:18have Infinity solution or many slow
- 13:21solution in here so you should be know
- 13:24about in our system we have
- 13:29three case
- 13:30one case is only one solution no
- 13:33solution and infinity minus Lu solution
- 13:38and for the next
- 13:41for the next we talk about the uh
- 13:45the system of equation like X Plus y
- 13:49equal 1 and 2x plus 2y equal
- 13:532. so you you change you can check about
- 13:56this equation X Plus y equals one and
- 14:00two X plus two y equal to so this one
- 14:03when you divide by two you got X
- 14:06plus y equal to one so between equation
- 14:091 and equation two are equal
- 14:12so when equal it means that you have
- 14:15many slow many solution if you write X
- 14:19Plus y equals 1 and 2x plus 2y equal
- 14:24equal 2. so this is
- 14:27this system or linear equation have many
- 14:29slow solution because the graph the
- 14:32graph is redone or in the same policy
- 14:36the same position
- 14:40and the next for example a graphical
- 14:43solution so you can solve the system or
- 14:46linear equation by a graphical solution
- 14:49use a graph to find solution
- 14:52the follow of system of equity equation
- 14:57example you have equation one is X Plus
- 15:01y equal 3 and equation two is X Y minus
- 15:06X is equal to Pi
- 15:08so in this case done don't be confused
- 15:12about this point
- 15:14uh in
- 15:15our country when the use about the
- 15:18system
- 15:21system equation
- 15:26equation they write in a curly bracket
- 15:29like X
- 15:31plus y equals 3 and Y minus eight equal
- 15:37to equal to 5. so this is right in our
- 15:41country you write in curry black blanket
- 15:46but
- 15:47other country or on glow section or
- 15:51something in Singapore in UK they write
- 15:55about the system of linear equation like
- 15:58this one
- 15:59yeah I like this one they do not need to
- 16:02juice about the curry curry blanket
- 16:06so please remember remember about this
- 16:09point
- 16:10and the next the next reveal
- 16:14solution through graphing about the
- 16:16equation and identify the
- 16:20resist identify the craft point
- 16:22intersection we can find solution
- 16:26in here so what is the
- 16:33the line that represents who the
- 16:35equation one and which line is
- 16:38represented to the equation two this is
- 16:41equation one and this is equation two
- 16:43so equation one is when we can we can
- 16:47write into this here Y is equal to
- 16:50Negative X plus 3 and this is uh y equal
- 16:55to X plus pi so you can draw about the
- 17:00line or the graph of this equation like
- 17:04you give the value of X and Y
- 17:07so when you get 8 0 y E3 and y0 and X is
- 17:13equal to 3 or so
- 17:15and if this here is like X and Y
- 17:18again y you can
- 17:23you can give like uh x0 and 5 y 0 this
- 17:28is the negative of of I
- 17:31so in here you can guess which one is
- 17:34the equation 1 and which line is the
- 17:36equation two the green one
- 17:39and the the blue one so the green one it
- 17:43means that
- 17:45the green one is equation one like
- 17:49X
- 17:51plus y equal to 3.
- 17:53and the blue one is y minus x equal to 2
- 17:585.
- 17:59but you see this equation
- 18:02this line the green line and the blue
- 18:05light blue line intersection at this
- 18:08point it means that when you
- 18:11orthogonal or projects
- 18:14project orthogonal on x-axis you got
- 18:17-1
- 18:18and project on
- 18:21y-axis you got this is four
- 18:24so the intersection between red between
- 18:28blue line and green line is at the point
- 18:31X and Y that X is equal to -1 and y
- 18:36equal to 2 4. so
- 18:39our system of unit equation x
- 18:42plus y equal 3 and Y
- 18:46minus x equal to 5 we got the value is X
- 18:51and Y
- 18:53that x equal to minus 1 and y
- 18:56equal to 2 4 this is our slow solution
- 19:02so this is only my explanation about the
- 19:05system of linear equation in
- 19:07our Cartesian plane like only in plan X
- 19:12and Y
- 19:13so now
- 19:15we check for the intersection Point
- 19:18remember the must-have either one
- 19:21solution Infinity solution or no
- 19:24solution at at all so which one
- 19:27the following all the graphs so that our
- 19:31uh intersection of our
- 19:35equation one and equation two we have
- 19:37only one one point only one point so the
- 19:42system of linear equation have only one
- 19:45slow solution that x equals to minus one
- 19:49and y equal to to 4.
- 19:53and for the next
- 19:56we will talk about the system of linear
- 19:59equation also so now you know already
- 20:02when you think about the system only
- 20:05equation you can solve the linear
- 20:07equation by our our example you have
- 20:11this graph and you have this line
- 20:14and this is the intersection of
- 20:18line Bond and line two so like this one
- 20:21is y0 and this is x0 so
- 20:25our system or linear equation have like
- 20:28X and Y
- 20:29equal to X rho N Y zero this is about
- 20:34the solution of our query equation
- 20:38and
- 20:40also this is in plan
- 20:43also X and Y but we have three
- 20:47example we have equation one
- 20:51equation 2 and equation 3. equation
- 20:55three
- 20:56so this is I can call this is line one
- 21:00line two and line three also
- 21:03line one line two and line three you can
- 21:06think about
- 21:09the intersection of line one line two
- 21:11and line three
- 21:13so line one can be intersection with
- 21:18line three and line two
- 21:23line three and line two line one
- 21:26but
- 21:28we have
- 21:30different point
- 21:32example
- 21:33line one intersection with line three we
- 21:37have this one is x0 and Y wise row
- 21:42line one intersection with
- 21:45line two
- 21:46with line two we got X row but this one
- 21:49is y0 print is it different from y0 it
- 21:54is not at the same point
- 21:56so and line two intersection with line
- 21:59three
- 22:01line tool in the section with line 3 it
- 22:04means that you got about X1
- 22:07and this is we can call Y y1 so line one
- 22:12in the section we have
- 22:14I can write this is A1
- 22:17A2 and a A3 so intersection between
- 22:22three line it is not at the same point
- 22:25it's different point line one in the
- 22:27section line two line one into six and
- 22:29line three line two in the section with
- 22:32line one line one in the section with
- 22:34line three uh line two and line three it
- 22:37is the different place different place
- 22:40if different place it means that we
- 22:43cannot
- 22:44we cannot say that this equation one
- 22:48equation two and equation three have no
- 22:52solution
- 22:53because it is different point
- 22:55example line one and line two is true
- 22:58but line one and line three it is not
- 23:00true this is four
- 23:02it is not example it is not 2 equal to
- 23:07or two
- 23:09equal to 3 so it is not true
- 23:12so this is no slow no solution
- 23:17and for the next
- 23:21this graph it means that line one
- 23:24line one line two and line three
- 23:26intersection in the same point
- 23:29only one point like this one I can call
- 23:31this this a
- 23:33half about the Y zero
- 23:36and this is an x x row so it means that
- 23:40line one intersection with line two
- 23:44intersection with line three
- 23:47have
- 23:48about in here
- 23:51like X row and
- 23:54and vice row if it have x row and y0 in
- 23:58the same point it means that equation
- 24:00one equation two equation three
- 24:04combine each other we can call this the
- 24:06system of linear equation
- 24:08so system of linear equation in line one
- 24:10line two and line three it means that we
- 24:13have one intersection so the system have
- 24:16only one slow solution
- 24:22and consider the first picture below
- 24:24while three line intersect with one
- 24:28another there is no common point in the
- 24:31section where all three line meet at one
- 24:35point
- 24:36and there is no solution of three
- 24:39equations
- 24:40remember a solution of a point X and Y
- 24:44which certify all three equations
- 24:48in the case of second feature the line
- 24:51intersection at common point this means
- 24:54that there is no solution to three
- 24:57equation
- 24:58like I asked Can you about
- 25:02and
- 25:04the next we talk about the first
- 25:09the first thing I talk only about in
- 25:12plan
- 25:12in plan in plan like extreme o x
- 25:18o y prime or Y and extreme o x this is
- 25:24in plan
- 25:27this only plan but for next point I will
- 25:30introduce you about intersection in
- 25:34spice
- 25:36X
- 25:38y and z
- 25:40this is only o in space
- 25:42so in space
- 25:45this is only juice about the
- 25:48variable X and Y
- 25:50and this is we use x
- 25:53Y and Z and halves Vector I
- 25:58Z and K also
- 26:00this is only I and z
- 26:05so
- 26:06now when we talk on Space we cannot
- 26:10think about the
- 26:12intersection between line intersection
- 26:15plane
- 26:16another plan to another plan like you
- 26:19think on your wall or at your house the
- 26:23the wall you think this is one plan and
- 26:26your
- 26:27floor this is one plane intersection
- 26:29between your wall and your fall this is
- 26:33only one one line example in here if I
- 26:39I draw about this
- 26:43this plan this is a call
- 26:45plan p
- 26:47and another one like that I put
- 26:52plan
- 26:54Q
- 26:56so intersection between plan p and Q
- 27:00p and so this is one one line over here
- 27:03so this is the intersection of plan p
- 27:07and Q
- 27:08so now we go to our relation for next
- 27:12you may recall the equation in three
- 27:16variable sex to X plus 4y and minus 5z
- 27:22equal to 8 from a plane about
- 27:25we we were looking to intersection of
- 27:29line in other to identify any possible
- 27:32solution when graphical solving system
- 27:35of equation in three vertical
- 27:38we look
- 27:40we look for intersection of plan
- 27:43this point in the section give X Y and Z
- 27:46in here X Y and Z that certify all
- 27:51equation in system
- 27:53so what high of solution are possible
- 27:56when working with three variable
- 27:59consider the following picture involved
- 28:02to plan
- 28:04which are given by two equation in three
- 28:07variables
- 28:09so the first example I showed you only
- 28:13one
- 28:15uh equation in two variable but now I
- 28:20will show you about one equation in
- 28:22three variables so what happened next
- 28:26so this is like plan
- 28:28P right plan p this is like plan Q then
- 28:34Q so this is the intersection of p and Q
- 28:38this is intersection between pen p and Q
- 28:42so p and show this is the parameter line
- 28:46also in our plan or in our space I have
- 28:52you study already in grade 12 the
- 28:54intersection between plan and plan you
- 28:57got the parameter of the query uh
- 29:00equation in line
- 29:03so now
- 29:05we will go to see this is three plan
- 29:09three plan also
- 29:11we get about a new plan of X Y and Z the
- 29:15coordinator
- 29:18and this is also a new plan that you got
- 29:22from intersection plan
- 29:26this is also when you have this is
- 29:29intersection between a
- 29:34another plan
- 29:40now
- 29:42seeing how three equations in three
- 29:44verbal can be have no solution a unique
- 29:48solution intersection in the lines uh
- 29:51resulting in Infinity solution
- 29:55it is also possible that three equations
- 29:58graph the same plane
- 30:00which also lead to infinity minutes low
- 30:03solution
- 30:07like equation like X
- 30:10so this is informable X
- 30:13plus Y and plus uh
- 30:18minus 2z and plus 4 W equal to X
- 30:23with more than three variables are often
- 30:25called hyperplane
- 30:28hyperplane you may soon release that it
- 30:31is tricky to draw the graph of
- 30:34hyperplane
- 30:36through the toll of linear algebra we
- 30:40can algebraically examine this type of
- 30:43system which are difficult to graph
- 30:46in the following section we will
- 30:48consider this algebraic tool also
- 30:57so this is only xxi
- 31:01we talk about the graphical to find
- 31:03about the point X1 and y1 between uh
- 31:09equation 1 and equation two so when you
- 31:12do you can write in our curly blanket is
- 31:15X1 Plus
- 31:173y equal one and four x
- 31:22minus y is equal to 1. so you can
- 31:27multiply this by negative four
- 31:32you got minus 4 X Plus 3y
- 31:36equal 1 and 4x
- 31:39this is
- 31:41equal to -4
- 31:43F4 and 4x minus y equal to 1.
- 31:48so X that's all you got for y
- 31:53equal to
- 31:55uh this is minus 4 equal to 3.
- 31:59-3
- 32:00so you got y this is equal to minus
- 32:03three oh minus four is three over four
- 32:05you can substitute Y into y you got
- 32:11for x
- 32:13minus 3 over 4y equal to 1. so again you
- 32:19can find about y this is equal to
- 32:21something
- 32:22so when you do this one it is not by the
- 32:26equation
- 32:29when you do this one for our design you
- 32:31got zero point in here
- 32:34because
- 32:35our exercise they they want you to find
- 32:39about the X one and Y one
- 32:43which lie on the Boss line
- 32:45biographically
- 32:47so they want you to solve this
- 32:50system of linear equation by graph
- 32:54when you saw by a substitute or by other
- 32:57operation it is not
- 33:00you cannot get the score for your
- 33:03solving
- 33:04please remember about this point before
- 33:06you sold about the point or other
- 33:09equation or other exercise you should be
- 33:13read be carefully about hypothesis what
- 33:16we want you to solve about this hxi
- 33:19please remember about this point
- 33:22and this is on low only about it's
- 33:25excited or so
- 33:28and it's excite 1.1 and 0.3
- 33:34the top in general
- 33:37you have a system of K equation okay
- 33:40equation it means that up to you
- 33:44in two variable in two word ball it
- 33:47means that the UK
- 33:51bigger or small bigger or equal to two
- 33:54explain the geometric
- 33:58significance of no solution
- 34:01unique solution and infinity solution
- 34:05if you want to know about the equation
- 34:08the system of K equation in two variable
- 34:12have no solution what does mean if it
- 34:15has no solution unique solution and
- 34:19infinity solution in here
- 34:22so explain in geometry
- 34:26significant
- 34:28so this is a sign that we will talk in
- 34:30our class
- 34:31before
- 34:33you meet me in class you should be
- 34:35thinking about this all this exercise
- 34:38but
- 34:39you think and you do by yourself or with
- 34:42your group
- 34:44and when you meet me in the class I will
- 34:46ask you to solve about this problem on
- 34:49whiteboard or we can top each other in
- 34:51group in our class
- 34:53foreign
- 34:57[Music]
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This page contains the full transcript of Chapter 01: System of linear equation and matrix V1 by Institute of Digital Technology - IDT, generated from the public captions YouTube serves with the video. The transcript has 4,064 words across 677 segments, with the original timestamps preserved so you can click any line to jump to that moment in the embedded player.
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