Giáo án song ngữ Đại số 9 - Period 19: Review and supplement the concepts of functions

Nội dung text: Giáo án song ngữ Đại số 9 - Period 19: Review and supplement the concepts of functions

1. Teacher : Trần Quốc Sĩ Van Thuy secondrary school Day leson plans: / /2018 Day to teach / /2018. Class 9B Chapter I – LINEAR FUNCTIONS Period 19: Review and supplement the concepts of functions I/ GOAL: 1. Knowledge - Students understand the concept of functions, variables; Functions can be given by table, by formula. - When y is a function of x, it can be written y=f(x), y=g(x), Value of function y =f(x) tại x0, x1, denoted by f(x0), f(x1), - Graph of functions y = f(x) is a collection of all the point of the matching pair matching values (x; f(x)) on the coordinates plane. - The first_standard has not function variable, nghịch biến trên R. 2. Skills - Know the value of the function when the variable is known. - The symbol of the couple (x, y) on the equilibrium plane. - Draw the function y = ax. 3. Attitude - Drawing accurate, careful in learning. II/ PREPARE - Student: Read lesson 1. Review the graphs learned in class 7. - Teacher: Lesson plan, text book, small table. III/ TEACHING PROCESS: 1. Stable institutions: 2. Check Oldest: ( minutes): 3. New lesson: In class 7, we have been introduced to functions, some quantitative examples, flat- plane concepts; Graphics function y = ax. Chapter II - The number 9, outside of the archives are also added additional concepts: Function, variable function; Research the most important and relative position between two straight line. Today's lesson, we will remind and add ideas on functions. Activity of teachers Activity of student Use board ACTIVITY 1. Khái niệm hàm số. (15 minutes) - When the quantity y is - Aanswer. 1- The concept of function. called the function of the change quantity x? - Write on the board. - Write lesson - How many ways to have - Given formula or • y is called a function of x if: function? table. - A quantity y varies according to - Given Example on screen. - Observe a changing quantity x. - Why y is a function of x ? - y depend on the - Each value of x, we always change of x identify only one corresponding Lesson plan Algebra 9
2. Teacher : Trần Quốc Sĩ Van Thuy secondrary school each value of x value of y. specify a y identities When, y is called function and x value of y is called variable. - Why formula in example - Answer. 1a is a function of x ? * f(0); f(1); ; f(a) is value of - When a function is given - Listen function y= f(x) at x=0; x= 1; by the formula y = f(x), that ; x=a. the variable x only get the value wich make f(x) defined. * The function: y= 3x+1 and - Observe, follow the y= 2x 4 instructions. y * The function x * The function y 1 x f(3) = 9 We say the - Listen corresponding value of y when x = 3 is 9 - We understand the symbols - Is the value of the f(0), f(1) function x = 0, x = 1 - Ask students ?1 - Personal work done in notebooks. - Ask some students to report - Report result. the results. ACTIVITY 2. The graphs of functions. (10 minutes) - Ask students to do ?2 - Go on the board and 2- The graphs of functions: write your answer. ?2 - The set of points A, B, C, - For table D, E, F on the coordinate example1a plane are the corresponding value pairs given by the table? - What the graph of function - Is the set of points in 2a ? A, B, C, D, E, F - What are the graphs of - Is a straight line. functions y = 2x? b) Functions y = 2x passing point with coordinates O (0,0); A (1, 2) Lesson plan Algebra 9
3. Teacher : Trần Quốc Sĩ Van Thuy secondrary school - What the graph of function - Answer. y = f(x) ? The sets of the points representing the corresponding value pairs (x; f (x)) on the coordinate plane is called the graph of the function y = f (x). ACTIVITY 3. Increeasing or decreasing functions. (10 minutes) - Ask students to do ?3 - Calculate and fill 3- Increeasing or decreasing table. functions: * Given function y=2x+1 - Is the expression 2x + 1 - With all executables defined with any value of x? x. - When x increases - Also increased corresponding to the value of y? - Function y = 2x + 1 - With all executables variable on R x. * Given function y = -2x+1 x1, x2 R - Expression -2x + 1 define x1 f(x2) corresponding value of y ? value of y decreases. y = f(x) decreasing on R - We say that the function y - Listen. = -2x + 1 is inversely proportional to R - What do you understand - Answer. the variable function variable? Lesson plan Algebra 9
4. Teacher : Trần Quốc Sĩ Van Thuy secondrary school IV. PRACTICE ( 10 ph) - Exercises 2,3 tr 45 / book. 1 a- Given function f(x)= x 6 when f(-3) equal: 3 A: 9 B: 3 C: 5 D: 4 1 b- Given function g(x)= x 2 . when f(3) equal: 3 A: 1 B: 3 C: -1 D: 2 c- The function y= f(x)= -7 +3x is function A: increasing. B: increasing, decreasing to both. C: decreasing. D: Both A, B, C is false. IV. HOME WORKS (1 minutes) Sentence 1: Given function f(x) = ax4 – bx2 + x +3 (a, b is constant). Given f(2)= 17. Evalute f(-2) Sentence 2: Prove the graph of function y = f(x) = 3 x x 3 is a point - Prepare to practice  Lesson plan Algebra 9