北京 景山 学校 数学系
Advanced Geometry @ MATHEMATICS @ Junior 8  。2009-2010
jiguanglaoshi@gmail.com

<== previous month                  Home Page                 Next month  ==>
[2] November
[updated : 2009/12/02]
Date
 Activities / Objectives
  Images / Home Work
 Remarks / Images
 References / Linkis
Wednesday

Nov. 11

16:05 -16:45
  • Comments on the returned Assignment #2 (show on animated pictures of the Euler's line and circle)
    • typical mistakes in some demonstrations
    • lack of verbal presentation
    • many unreadable or durty papers
    • many stupid copies from others
    • very few student can really show an articulate understanding of the problem, and write it in proper verbal English.
  • Exercises of demonstrations with inscribed angles (Assignment #3).
il    quad_insc 		Many students have copied their home work on someone else's, most of the time with stupid mistakes (wrong notations).
As a consequence there will be no more compulsery home work !
Instead there will be an individual test  every other week.
  • Pei & Yufei on the black board
    to prove the equality of the limit insribed angle with the "regular" inscribed angle.
Assignement #2 ANSWERS
(Euler's line & Euler's circle)

Assignment #3
(demos about inscribed angles)
Thursday

Nov. 12

16:05 -16:45
  • Complementary exercises about the golden number : calculations and construction in a rectangle and in an isoceles triangle.
RoR

ToR
 Assignment #4

construc_rector

gtr2
Most students made a confusion between the research and construction of the golden number and its inverse
(called the golden section)

phy

phi-1

construc_trior

 Assignment #4
(special problems)

Construction of the
Golden Number

History of the Golden Number
(or Golden Ratio)


ANSWERS / Exercises Golden Number
Construction of the Golden Rectangle
and of the Golden Triangle


ANSWERS / Exercises Golden Number
Construction of the Golden Rectangle
and of the Golden Triangle


ANSWERS / Exercises Golden Number
Construction of the Golden Rectangle
and of the Golden Triangle
Wednesday

Nov. 18

16:05 -16:45
  • Introduction to VECTORS in the Plane
    • Examples in Physics :
      • Forces
      • Speeds
      • Magnetic Fields
    • Sets of ordered pairs of points :
    • vect
      where (A,B,B1,A1) is a parallologram
  • Addition of Vectors :
    • three cases (see pictures).
    • Fundamental relation of Addition :
      Chasles
    • Note that the "sum of the distances" is NOT equal to the "distance of the sum" :
                  AB + BC > AC
 Addition of two Vectors
Sum1

VS2






VS3
Thursday

Nov. 19

16:05 -16:45   





Complete and prepare the exercises
on sheet #5
for Wed. Nov. 25

Exercises #5
(addition and substracion of Vectors)





ANSWERS / Exercises Golden Number
Construction of the Golden Rectangle
and of the Golden Triangle

Wednesday

Nov. 25

16:05 -16:45   
    • Return of Assignment # 4 (special Pb) :
    Correction of the two special problems without using the calculations on the angles, but by using the properties of a ROTATION of 60° around a fixed point.
    • Correction of exercise III and IV about vectors.
A4E1
IC = BJ ? & <(CKI) = 60° ?
A4E2
D,I,J, are on the same line ?
 		Exercises #5
(addition and substraction of Vectors)

Assignment #5
(addition and substraction of Vectors)
Thursday

Nov. 26

16:05 -16:45
  • Properties of the Addition of Vectors
    • Order of addition
    • Associativity of Addition
    • Vector Null
    • Opposite of a vector
  • Definition of the Multiplication of a Vector by a real number.
    		•


    Ass6

    Exercises #5
    (addition and substraction of Vectors)

    Assignment #5
    (addition and substraction of Vectors)