14-240/Classnotes for Monday September 15: Difference between revisions

From Drorbn
Jump to navigationJump to search
(more typesetting. Do we have the proof environment here?)
No edit summary
Line 1: Line 1:
{{14-240/Navigation}}
Definition:
Definition:
Subtraction: if <math>a, b \in F, a - b = a + (-b)</math>.
* Subtraction: if <math>a, b \in F, a - b = a + (-b)</math>.
Division: if <math>a, b \in F, a / b = a \times b^{-1}</math>.
* Division: if <math>a, b \in F, a / b = a \times b^{-1}</math>.


Theorem:
Theorem:


8. <math>\forall a \in F</math>, <math>a \times 0 = 0</math>.
* 8. <math>\forall a \in F</math>, <math>a \times 0 = 0</math>.
proof of 8: By F3 , <math>a \times 0 = a \times (0 + 0)</math>;
proof of 8: By F3 , <math>a \times 0 = a \times (0 + 0)</math>;
By F5 , <math>a \times (0 + 0) = a \times 0 + a \times 0</math>;
By F5 , <math>a \times (0 + 0) = a \times 0 + a \times 0</math>;

Revision as of 08:08, 17 September 2014

DBN: Classes: 2014-15: 14-240 / Navigation
Welcome to Math 240!
(additions to this web site no longer count towards good deed points)
# Week of... Notes and Links
1 Sep 8 About This Class, What is this class about? (PDF, HTML), Monday, Wednesday
2 Sep 15 HW1, Monday, Wednesday, TheComplexField.pdf,HW1_solutions.pdf
3 Sep 22 HW2, Class Photo, Monday, Wednesday, HW2_solutions.pdf
4 Sep 29 HW3, Wednesday, Tutorial, HW3_solutions.pdf
5 Oct 6 HW4, Monday, Wednesday, Tutorial, HW4_solutions.pdf
6 Oct 13 No Monday class (Thanksgiving), Wednesday, Tutorial
7 Oct 20 HW5, Term Test at tutorials on Tuesday, Wednesday
8 Oct 27 HW6, Monday, Why LinAlg?, Wednesday, Tutorial
9 Nov 3 Monday is the last day to drop this class, HW7, Monday, Wednesday, Tutorial
10 Nov 10 HW8, Monday, Tutorial
11 Nov 17 Monday-Tuesday is UofT November break
12 Nov 24 HW9
13 Dec 1 Wednesday is a "makeup Monday"! End-of-Course Schedule, Tutorial
F Dec 8 The Final Exam
Register of Good Deeds
Class Photo
Add your name / see who's in!
14-240-Splash.png

Definition:

  • Subtraction: if .
  • Division: if .

Theorem:

  • 8. , .
                   proof of 8: By F3 , ;
                               By F5 , ;
                               By F3 , ;
                               By Thm P1,.
       
        9.  s.t. Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle 0 \times b = 1}
;
           Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \forall b \in F}
 s.t. Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle 0 \times b \neq 1}
.
                   proof of 9: By F3 , Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \times b = 0 \neq 1}
.
       
       10. Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle (-a) \times b = a \times (-b) = -(a \times b)}
.
     
       11. Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle (-a) \times (-b) = a \times b}
.
      
       12. Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle a \times b = 0 \iff a = 0 or b = 0}
.
                   proof of 12: <= : By P8 , if Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle a = 0}
 , then ;
                                     By P8 , if Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle b = 0}
 , then Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle a \times b = a \times 0 = 0}
.
                                => : Assume Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle a \times b = 0 }
 , if a = 0 we are done;
                                     Otherwise , by P8 , Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle a \neq 0 }
 and we have Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle a \times b = 0 = a \times 0}
;  
                                                 by cancellation (P2) , Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle b = 0}
.

Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle (a + b) \times (a - b) = a^2 - b^2} . 

        proof: By F5 , Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle (a + b) \times (a - b) = a \times (a + (-b)) + b \times (a + (-b))}

                                               
                                               Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle = a^2 - b^2}

Theorem : 

        Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \exists! \iota : \Z \rightarrow F}
  s.t.
              1. Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \iota(0) = 0 , \iota(1) = 1}
;
              2. Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \forall m ,n \in \Z, \iota(m+n) = \iota(m) + \iota(n)}
;
              3. Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \forall m ,n \in \Z, \iota(m\times n) = \iota(m) \times \iota(n)}
.

        Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \iota(2) = \iota(1+1) = \iota(1) + \iota(1) = 1 + 1;}

        Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \iota(3) = \iota(2+1) = \iota(2) + \iota(1) = \iota(2) + 1;}
 
        ......                                                                          
     
        In F2 , Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle 27 ----> \iota(27) = \iota(26 + 1)}

                                        Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle = \iota(26) + \iota(1)}

                                        Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle = \iota(26) + 1}

                                        
                                        Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle = \iota(2) \times \iota(13) + 1}

                                        Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle = (1 + 1) \times \iota(13) + 1}

                                        Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle = 0 \times \iota(13) + 1}

                                        Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle = 1}
Retrieved from "https://drorbn.net/index.php?title=14-240/Classnotes_for_Monday_September_15&oldid=13314"