Tham khảo tài liệu 'symbols of addition 10', ngoại ngữ, anh ngữ phổ thông phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | THEA MATH REVIEW Examples x 5 Contains no variable y so you cannot isolate y. This is not a function. 2x 3y 5 Isolate y 2x 3y 5 -2x -2x _3y -2x 5 y - ỉ3 5 3x 3 This is a linear function of the form y mx b. x2 y2 36 Contains y2 so it is not a function. y 5 There is no way to isolate y with a single equation therefore it is not a function. Function Notation Instead of using the variable y often you will see the variable f x . This is shorthand for function of x to automatically indicate that an equation is a function. This can be confusing f x does not indicate two variables f and x multiplied together it is a notation that means the single variable y. Although it may seem thatf x is not an efficient shorthand it has more characters than y it is very eloquent way to indicate that you are being given expressions to evaluate. For example if you are given the equation f x 5x - 2 and you are being asked to determine the value of the equation at x 2 you need to write evaluate the equation f x 5x - 2 when x 2. This is very wordy. With function notation you only need to write determinef 2 . The x inf x is replaced with a 2 indicating that the value of x is 2. This means thatf 2 5 2 - 2 10 - 2 8. All you need to do when given an equationf x and told to evaluate f value replace the value for every occurrence of x in the equation. Example Given the equation f x 2x2 3x 1 determine f 0 and f -1 . f 0 means replace the value 0 for every occurrence of x in the equation and evaluate. f 0 2 0 2 3 0 1 0 0 1 1 f -1 means replace the value -1 for every occurrence of x in the equation and evaluate. f 0 2 -1 2 3 -1 1 2 1 -3 1 2 - 3 1 0 135 ---------------------------------- THEA MATH REVIEW -------------------------------------- Families of Functions There are a number of different types or families of functions. Each function family has a certain equation and its graph takes on a certain appearance. You can tell what type of function an equation is by just looking at the equation or its
