Chun Pong--Derek--Chow>>HELLO~
Chun Pong--Derek--Chow>>are you the real prof?
Prof Yan--Min-->>no i am Bong
Siu Him--Lau>>there is no chatting session today in the calender. what are the topics today?
Chun Pong--Derek--Chow>>find it in COURSE MATERIAL
Prof Yan--Min-->>I don't know?
Prof Yan--Min-->>may be Pro Yan firget to type in the calander!
Siu Him--Lau>>more people now
Siu Him--Lau>>the problem of double prof is still here.
Prof Yan--Min-->>yes ar
Chun Pong--Derek--Chow>>may be prof don;'t come tonight
Siu Him--Lau>>is that if all variables are nonfree, then all columns are pivot?
Prof Yan--Min-->>yes
Prof Yan--Min-->>provided that the system is consistent
Siu Him--Lau>>what is trivial solution?
Prof Yan--Min-->>for Ax=0,x=0 is trival solution
Prof Yan--Min-->>since there maybe some sol eg x=(a,b,c) a,b, c, are not all zero
Prof Yan--Min-->>IT depend on the matrix A
Shuk Fan--Chau>>is there any difference bewteen matrix and square matrix?
Prof Yan--Min-->>of course!
Prof Yan--Min-->>square matrix is n*n
Prof Yan--Min-->>matrix not necessary n*n
Chun Pong--Derek--Chow>>where can i find the record of the last chatting session?
Prof Yan--Min-->>I think u can't find it!
Chun Pong--Derek--Chow>>why?
Prof Yan--Min-->>it matter of design ,just the technician know!
Chun Pong--Derek--Chow>>but prof Man said that we can find the complete record in the internal mail
Prof Yan--Min-->>let me see
Prof Yan--Min-->>but i really can't find it
Chun Pong--Derek--Chow>>ME TOO
Prof Yan--Min-->>maybe i ask pro Yan and reply u next time
Siu Him--Lau>>in Discussion Board
Chun Pong--Derek--Chow>>but it is not the complete record!
Siu Him--Lau>>really? ihave not seen yet in fact
Prof Yan--Min-->>It said there is attachment but i can't found it.
Chun Pong--Derek--Chow>>the attachment is just the text of the mail!
Prof Yan--Min-->>iwant to know is the online material just released today?
Chun Pong--Derek--Chow>>actually not, the course material has already tell us the schedule
Siu Him--Lau>>can u see download in the yellow buttons?
Siu Him--Lau>>Reply Reply Privately Quote Download
Prof Yan--Min-->>but the thing u download is not the record
Siu Him--Lau>>oh
Siu Him--Lau>>is that a test for us?
Chun Pong--Derek--Chow>>it's just the text!
Prof Yan--Min-->>i think that there will be some quizz on saturday tutorial
Chun Pong--Derek--Chow>>oh god
Prof Yan--Min-->>have all of u readind news today?
Siu Him--Lau>>what news ?
Prof Yan--Min-->>one professor in BU was selected as commite of Noble Prize
Prof Yan--Min-->>His research topic is Game Thoery
Chun Pong--Derek--Chow>>what was that?
Prof Yan--Min-->>And do u know who is John Nash
Siu Him--Lau>>??????????
Prof Yan--Min-->>Game Theory is mathematical theory which deal with problem of competition
Prof Yan--Min-->>Do u know the film"A Beautiful Mind"?
Chun Pong--Derek--Chow>>.................no
Prof Yan--Min-->>It's the story about John Nash
Siu Him--Lau>>i know that film but i dont know what the theory is
Prof Yan--Min-->>Who is a genius mathematican and finally win the Noble Prize in Econ
Prof Yan--Min-->>In fact the text book used in the game theory course in UST is not so hard to read
Prof Yan--Min-->>if u r interest u can but it in the UST book store
Chun Pong--Derek--Chow>>how much is that?
Prof Yan--Min-->>I forget lu
Siu Him--Lau>>i got a Q in http://algebra.math.ust.hk/linear_equation/07_sizeprinciple/exercise1_answer.shtml in Q.5, i dont understand why "if the system has solutions (for some choices of right side, such as a = b = c = d = e = 0), then the solutions are also the solutions of the following subsystem"
Siu Him--Lau>>1.23x1 - 3.75x2 + 0.02x3 = a
Siu Him--Lau>> - 4.57x2 + 3.34x3 = b
Siu Him--Lau>>+ 7.98x3 = d
Siu Him--Lau>>oh wrong position
Prof Yan--Min-->>let me see
Prof Yan--Min-->>ic
Prof Yan--Min-->>bcos
Prof Yan--Min-->>in the sys of eq as following
Prof Yan--Min-->>1.23x1 - 3.75x2 + 0.02x3 = a
Prof Yan--Min-->> 4.57x2 + 3.34x3 = b
Prof Yan--Min-->>7.98x3 = d
Prof Yan--Min-->>it is the row echelon form right?
Prof Yan--Min-->>and all column has pivot!right
Prof Yan--Min-->>so the system have unique solution!right?
Prof Yan--Min-->>so base on this system
Prof Yan--Min-->>if we add two more equation
Siu Him--Lau>>i dont notice that it is the echelon form
Prof Yan--Min-->>and the system still consistent
Prof Yan--Min-->>than the system of 5 equation must have the same solution as sys of 3 eq
Prof Yan--Min-->>ok
Prof Yan--Min-->>let me type it in better form
Siu Him--Lau>>?
Prof Yan--Min-->>1.23x1 - 3.75x2 + 0.02x3 = a
Prof Yan--Min-->> 4.57x2 + 3.34x3 = b
Prof Yan--Min-->>oh sorry i can't do that
Prof Yan--Min-->>first of all
Prof Yan--Min-->>do u think that the system of 3 equation have unique solution?
Siu Him--Lau>>yes
Prof Yan--Min-->>so if we add two more equation
Prof Yan--Min-->>but the new system of 5 equation is still consistent
Prof Yan--Min-->>than the solution must be the same as the old system of 3 equation
Siu Him--Lau>>is that possible that there is no solution?
Prof Yan--Min-->>because we assumed that the system is still consistent
Prof Yan--Min-->>it means that there is solution
Prof Yan--Min-->>consistent means solution exit!
Siu Him--Lau>>i fotgot that "if the system has solutions".................................................................
Prof Yan--Min-->>I think it's the end of today's tutorial bye bye
Siu Him--Lau>>real prof is not here today
Siu Him--Lau>>i need to cut myself into parts
Siu Him--Lau>>sorry this is wrong message