Member:Lam King Ho 98003010

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Educational Communication and Technology
(EDD5161A) PowerPoint Presentation Topic
Concept and Graphical Representation of Functions

• Group 21
• Member Lam King Ho (98003010)
• Lau Shu Fat (98003430)
• Li Chi Chung (98002690)
• Lam Wing Yin (98002850)
• Poon Hing Sheng (98249700)

GO
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• Concept of function
• Trigonometric function
• Logarithmic function
• Quadratic function
• Design Objectives
• Enhance students interest in understanding
  concept of functions and graphical representation
  of functions
• Provide a time-saving package for student/teacher
  in drawing graphs of different functions
• Enable a quick understanding of graphical
  variations upon changes of the coefficients
• Applicable to varies level of students ( Form 3
  to 5)

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• Guidelines to use
• Designed for students to use before or after the
  class but NOT in the class
• Designed as assisting program besides the
  classroom teaching
• Target Student
• Age Form two to Form four
• Ability Band 3
• Attitude self-motivated, eager to learn
• Authors part of design
• Concept of function ( Lam king ho Poon hing
  sheng )
• Trigonometric function ( Li chi chung Lau shu
  fat )
• Logarithmic function ( Lam wing yin Lam king ho
  )
• Quadratic function ( Lau shu fat Lam king ho )

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contents
Quadratic
Function
Log
Trigonometric
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Function
...
What is it ??
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Function f(x)x5
1
6
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Function f(x)x5
-3
2
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Function f(x)x5
4/9
49/9
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Mathematical Presentation
Go
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Let f(x) x 5 when x 1 , ?f(1) 1 5
6
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Let f(x) x 5 when x -3, ?f(-3) -3 5
2
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Let f(x) x 5 find f(4/9).
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Quadratic function
Quadratic function
y ax2 bx c
Go
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Use this to plot the following graphs
Then comparing their shapes
y x2 y -x2
y x2 - x - 6 y -x2 - x - 6
y 2x2 - x 5 y -2x2 - x 5
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y ax2 bx c
Eg.1
For a gt 0
Curve open upwards
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y ax2 bx c
For a gt 0
Curve open upwards
Eg.2
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y ax2 bx c
For a gt 0
Curve open upwards
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y ax2 bx c
For a lt 0
Curve open downwards
Eg.1
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y ax2 bx c
For a lt 0
Curve open downwards
Eg.2
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y ax2 bx c
For a lt 0
Curve open downwards
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y ax2 bx c
For c gt 0
y-intercept is positive
Eg.1
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y ax2 bx c
For c gt 0
(0, c)
y-intercept is positive
Eg.2
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y ax2 bx c
For c gt 0
(0, c)
(0, c)
y-intercept is positive
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y ax2 bx c
Eg.1
For c lt 0
y-intercept is negative
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Eg.2
y ax2 bx c
(0, c)
For c lt 0
y-intercept is negative
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(0, c)
y ax2 bx c
(0, c)
For c lt 0
y-intercept is negative
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y ax2 bx c
Eg.1
For c 0
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y ax2 bx c
For c 0
Eg.2
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y ax2 bx c
For c 0
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Exercise
Click the corrected answer
y ax2 bx c
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Congratulation
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Sorry, you are wrong!!
Try again..
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Trigonometric
Trigonometric
y sinx, y cosx, y tanx
Go
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Use this to plot the following graphs
Then comparing their shapes
1. sinx
2. cosx
3. tanx
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1. y sin(x)
Eg.1
2. y sin(2x)
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1. y sin(x)
Eg.2
2. y sin(2x)
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1. y sin(x)
2. y sin(2x)
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1. y cos(x)
Eg.1
2. y cos(2x)
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1. y cos(x)
Eg.2
2. y cos(2x)
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1. y cos(x)
2. y cos(2x)
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1. y tan(x)
Eg.1
2. y tan(2x)
x
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1. y tan(x)
Eg.2
2. y tan(2x)
x
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1. y tan(x)
2. y tan(2x)
x
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Exercise
Match the corrected order
Sin ,Cos, Tan
y
x
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Common Logarithms
Go
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Meaning of Common Logarithm
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• Using the graph of log y x to find
• the value of the following

a) log 2 ( )
0.3
b) log 5 ( )
0.7
c) log 10 ( )
1
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Exercise
For y 10x
When x 0.85, value of y is