1. REVIEW 1.1-1.3

2. A relation is a set of ordered pairs. {(2,3), (-1,5), (4,-2), (9,9), (0,-6)} This is a relation The domain is the set of all x values in the relation {(2,3), (-1,5), (4,-2), (9,9), (0,-6)} The range is the set of all y values in the relation {(2,3), (-1,5), (4,-2), (9,9), (0,-6)} domain = {-1,0,2,4,9} These are the x values written in a set from smallest to largest range = {-6,-2,3,5,9} These are the y values written in a set from smallest to largest

3. Domain (set of all x ’ s) Range (set of all y ’ s) 1 2 3 4 5 2 10 8 6 4 A relation assigns the x ’ s with y ’ s This relation can be written {(1,6), (2,2), (3,4), (4,8), (5,10)}

4. A function f from set A to set B is a rule of correspondence that assigns to each element x in the set A exactly one element y in the set B. Whew! What did that say? Set A is the domain 1 2 3 4 5 Set B is the range 2 10 8 6 4 A function f from set A to set B is a rule of correspondence that assigns to each element x in the set A exactly one element y in the set B. Must use all the x ’ s A function f from set A to set B is a rule of correspondence that assigns to each element x in the set A exactly one element y in the set B. The x value can only be assigned to one y This is a function ---it meets our conditions All x ’ s are assigned No x has more than one y assigned

5. Set A is the domain 1 2 3 4 5 Set B is the range 2 10 8 6 4 Must use all the x ’ s Let’s look at another relation and decide if it is a function. The x value can only be assigned to one y This is a function ---it meets our conditions All x ’ s are assigned No x has more than one y assigned The second condition says each x can have only one y, but it CAN be the same y as another x gets assigned to.

6. 1 2 3 4 5 2 10 8 6 4 Is the relation shown above a function? NO Why not??? 2 was assigned both 4 and 10

7. Evaluating Functions

8. So we have a function called f that has the variable x in it. Using function notation we could then ask the following: Find f (2). This means to find the function f and instead of having an x in it, put a 2 in it. So let ’ s take the function above and make brackets everywhere the x was and in its place, put in a 2. Don ’ t forget order of operations---powers, then multiplication, finally addition & subtraction Remember---this tells you what is on the right hand side---it is not something you work. It says that the right hand side is the function f and it has x in it.

9. Find f (-2). This means to find the function f and instead of having an x in it, put a -2 in it. So let ’ s take the function above and make brackets everywhere the x was and in its place, put in a -2. Don ’ t forget order of operations---powers, then multiplication, finally addition & subtraction

10. Find f (k). This means to find the function f and instead of having an x in it, put a k in it. So let ’ s take the function above and make brackets everywhere the x was and in its place, put in a k. Don ’ t forget order of operations---powers, then multiplication, finally addition & subtraction

11. Find f (2k). This means to find the function f and instead of having an x in it, put a 2k in it. So let ’ s take the function above and make brackets everywhere the x was and in its place, put in a 2k. Don ’ t forget order of operations---powers, then multiplication, finally addition & subtraction

12. Let's try a new function Find g(1)+ g(-4).

13. Find the domain for the following functions: Since no matter what value you choose for x, you won't be dividing by zero or square rooting a negative number, you can use anything you want so we say the answer is: All real numbers x. If you choose x = 2, the denominator will be 2 – 2 = 0 which is illegal because you can't divide by zero. The answer then is: All real numbers x such that x ≠ 2. means does not equal illegal if this is zero Note: There is nothing wrong with the top = 0 just means the fraction = 0

14. Let's find the domain of another one: We have to be careful what x's we use so that the second "illegal" of square rooting a negative doesn't happen. This means the "stuff" under the square root must be greater than or equal to zero (maths way of saying "not negative"). Can't be negative so must be ≥ 0 solve this So the answer is: All real numbers x such that x ≠ 4

15. Name all values of x that are not in the domain of the given function.

16. Given that x is an integer, state the relation representing each of the following by listing a set of ordered pairs. Then state whether the relation is a function or not. And {(0, -7), (1, -2), (2, 3), (3, 8)} IS THIS A FUNCTION??? YES

17. Given that x is an integer, state the relation representing each of the following by listing a set of ordered pairs. Then state whether the relation is a function or not. And {(-1, 3), (0, 0), (1, 3), (2, 24)} IS THIS A FUNCTION??? YES

18. Given that x is an integer, state the relation representing each of the following by listing a set of ordered pairs. Then state whether the relation is a function or not. And {(-8, 4), (-7, 3), (-6, 2), (-5, 1), (-4, 0), (-3, 1)} IS THIS A FUNCTION??? YES

20. The sum f + g This just says that to find the sum of two functions, add them together. You should simplify by finding like terms. Combine like terms & put in descending order

21. The difference f - g To find the difference between two functions, subtract the first from the second. CAUTION: Make sure you distribute the – to each term of the second function. You should simplify by combining like terms. Distribute negative

22. The product f g To find the product of two functions, put parenthesis around them and multiply each term from the first function to each term of the second function. FOIL Good idea to put in descending order but not required.

23. The quotient f /g To find the quotient of two functions, put the first one over the second. Nothing more you could do here. (If you can reduce these you should).

24. The Composition Function This is read “f composition g” and means to copy the f function down but where ever you see an x, substitute in the g function. FOIL first and then distribute the 2

25. This is read “g composition f” and means to copy the g function down but where ever you see an x, substitute in the f function. You could multiply this out but since it’s to the 3 rd power we won’t

27. Graphically, the x and y values of a point are switched. The point (4, 7) has an inverse point of (7, 4) AND The point (-5, 3) has an inverse point of (3, -5)

28. Graphically, the x and y values of a point are switched. If the function y = g(x) contains the points then its inverse, y = g -1 (x), contains the points x01234y124816 x124816y01234 Where is there a line of reflection?

29. The graph of a function and its inverse are mirror images about the line y = x y = f(x) y = f -1 (x) y = x

30. Find the inverse of a function : Example 1: y = 6x - 12 Example 1: y = 6x - 12 Step 1: Switch x and y: x = 6y - 12 Step 2: Solve for y:

31. Example 2: Given the function : y = 3x 2 + 2 find the inverse: Step 1: Switch x and y: x = 3y 2 + 2 Step 2: Solve for y:

32. Ex: Find an inverse of y = -3x+6. Steps: -switch x & y -solve for y y = -3x+6 x = -3y+6 x-6 = -3y

33. Find the zero of each function. Then graph the function. 1.) f(x) = 3x - 82.) f(x) = 19

34. Graphing Linear Equations and Inequalities

35. Graph 7x + y > –14 x y Pick a point not on the graph: (0,0) Graph 7x + y = –14 as a dashed line. Test it in the original inequality. 7(0) + 0 > – 14, 0 > – 14 True, so shade the side containing (0,0). (0, 0) Linear Equations in Two Variables Example

36. Graph 3x + 5y  –2 x y Pick a point not on the graph: (0,0), but just barely Graph 3x + 5y = –2 as a solid line. Test it in the original inequality. 3(0) + 5(0) > – 2, 0 > – 2 False, so shade the side that does not contain (0,0). (0, 0) Example Linear Equations in Two Variables

37. Graph 3x < 15 x y Pick a point not on the graph: (0,0) Graph 3x = 15 as a dashed line. Test it in the original inequality. 3(0) < 15, 0 < 15 True, so shade the side containing (0,0). (0, 0) Example Linear Equations in Two Variables

38. Graph this: