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9/5/13 Warm Up. To get from A to B you must avoid walking through a pond by walking 34 m south and 41 m east. How many meters would be saved if it were possible to walk through the pond ? Write you answer t o the nearest meter (you may use a calculator)
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9/5/13Warm Up • To get from A to B you must • avoid walking through a pond by • walking 34 m south and 41 m • east. How many meters would • be saved if it were possible to walk • through the pond? Write you answer • to the nearest meter (you may use a calculator) • 2. Find the distance between the two points (3, 4) and (-1, -2) • Write your answer in simplest radical form. 22 m 2√13
-7 -7 -2 -2 -1 -1 1 1 3 3 5 5 7 7 -6 -6 -5 -5 -4 -4 -3 -3 0 4 6 8 Inequality notation for graphs shown above. 2 Interval notation for graphs shown above. [ 0 2 4 6 8
Squared bracket means can equal 4 Rounded bracket means cannotequal -2 -7 -2 -1 1 3 5 7 -6 -5 -4 -3 0 4 6 8 2 Let's try another one. The brackets used in the interval notation above are the same ones used when you graph this. ( ] Set Notation: {x| -2 < x ≤ 4}
Example 1 Write each set using interval notation. Create a graph (visual representation using a number line). • { x | x ≥ 5 } • “All values of x such that x is greater than or equal to 5.” • Answer: [5, ∞) [ 5
Example 2 Write each set using interval notation. Create a graph (visual representation using a number line). • { x | -1 < x < 7 } • “All values of x such that x is greater than -1 but less than 7.” • Answer: (-1, 7) ( -1 ) 7
Example 3 Write using interval notation and set notation Answer: (2, ∞) { x | x > 2 } (
Example 4 Write using interval notation and set notation Answer: [-2, 1) { x | -2 ≤ x < 1} ) [
Example 5 Write using interval notation and set notation Answer: (-∞, -4) U (4, ∞) { x | |x| > 4 } ) (
Challenge Explain why the set { y | |y| ≥ 1 } is the same as (-∞, -1] U [1, ∞). Solution: After graphing the interval notation, we can see that the numbers between -1 and 1 are not solutions. [ ]
Functions • For each value of x (domain) there is only one value of y (range). • “One-to-one” • Domain • X-axis • Independent • Input • Range • Y-axis • Dependent • Output
HOW DO YOU KNOW IT’S A FUNCTION? • VERTICAL LINE (PENCIL) TEST • If every vertical line intersects the graph of a relation in no more than one point, then the graph is a function. • Are these functions? YES NO YES
(b) (a) (d) (c) Which Are Functions? (a) and (c)
The most common rules of algebra that limit the domain of functions are: Rule 1: You can’t divide by 0. Rule 2: You can’t take the square root of a negative number.
Example 1 Deciding Whether Relations Define Functions • Decide whether the relation determines a function. (a) M is a function because each distinct x-value has exactly one y-value.
Example 1 Deciding Whether Relations Define Functions (b) N is not a function because the x-value –4 has two y-values.
Example 2(a) Finding Domains and Ranges of Relations (page 442) • Give the domain and range of the relation. Is the relation a function? {(–4, –2), (–1, 0), (1, 2), (3, 5)} Domain: {–4, –1, 0, 3} Range: {–2, 0, 2, 5} The relation is a function because each x-value corresponds to exactly one y-value.
Example 2(b) Finding Domains and Ranges of Relations (cont.) • Give the domain and range of the relation. Is the relation a function? Domain: {1, 2, 3} Range: {4, 5, 6, 7} The relation is not a function because the x-value 2 corresponds to two y-values, 5 and 6.
Example 3(a) Finding Domains and Ranges from Graphs (page 442) • Give the domain and range of the relation in set notation. Domain: {–2, 4} Range: {0, 3}
Domain: Range: Example 3(b) Finding Domains and Ranges from Graphs • Give the domain and range of the relation in interval notation.
Example 3(c) Finding Domains and Ranges from Graphs • Give the domain and range of the relation in interval notation. Domain: [–5, 5] Range: [–3, 3]
Domain: Range: Example 3(d) Finding Domains and Ranges from Graphs • Give the domain and range of the relation in interval notation.
Domain: Range: Example 4(a) Identifying Function Domains, and Ranges • Determine if the relation is a function and give the domain and range. y = 2x– 5 y is found by multiplying x by 2 and subtracting 5. Each value of x corresponds to just one value of y, so the relation is a function.
Domain: Range: Example 4(b) Identifying Functions, Domains, & Ranges (cont.) • Determine if the relation is a function and give the domain and range. y = x2+ 3 y is found by squaring x by 2 and adding 3. Each value of x corresponds to just one value of y, so the relation is a function.
Domain: Range: Example 4(c) Identifying Functions, Domains, & Ranges (cont.) • Determine if the relation is a function and give the domain and range. x = |y| For any choice of x in the domain, there are two possible values for y. The relation is not a function.
Domain: Range: Example 4(d) Identifying Functions, Domains, and Ranges (cont.) • Determine if the relation is a function and give the domain and range. y is found by dividing 3 by x + 2. Each value of x corresponds to just one value of y, so the relation is a function.
Example #5 RANGE Find the domain and range in interval notation. Determine if the following is a function. DOMAIN D: [-3, 7] R: [-8, 2] Not it’s not a function.
RANGE Example #6 DOMAIN Find the domain and range in interval notation. Determine if the following is a function. D: (-∞, ∞) R: [2, ∞) It’s a function.
What is the domain and range of the following relation? Is this a function? Why or why not? { (-1,2), (2, 51), (1, 3), (8, 22), (9, 51) } Domain: -1, 2, 1, 8, 9 Range:2, 51, 3, 22, 51 Function: Yes, no domain (x) values repeat. It’s one-to-one. Passes vertical line test. For the following relation to be a function, X can not be what values? { (8, 11), (34,5), (6,17), (X ,22) } X cannot be 8, 34, or 6.