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Domain and Range
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Domain: In a set of ordered pairs, (x, y), the domain is the set of all x-coordinates (independent values). Range: In a set of ordered pairs, (x, y), the range is the set of all y-coordinates (dependent values).
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Closed Circles = number is included Open Circles = number not included
Interval Notation (a,b) implies a< x < b (a , b] implies a< x ≤ b x x a b a b Closed Circles = number is included Open Circles = number not included
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that direction infinitely
Interval Notation (a,∞) implies x > a [a , ∞) implies x ≥ a x x a a An arrow at the end of the line means the lines continues in that direction infinitely
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Interval Notation (-∞,b) implies x < b (- ∞ , b] implies x ≤ b b b
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Closed Circles = number is included Open Circles = number not included
Interval Notation [a,b) implies a ≤ x < b [a , b] implies a ≤ x ≤ b x x a b a b Closed Circles = number is included Open Circles = number not included
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Ex:{(2,3),(-1,0),(2,-5),(0,-3)} Domain: {2,-1,0} Range: {3,0,-5,-3}
The set of ordered pairs may be a limited number of points. Given the following set of ordered pairs, find the domain and range. Ex:{(2,3),(-1,0),(2,-5),(0,-3)} If a number occurs more than once, you do not need to list it more than one time. Domain: {2,-1,0} Range: {3,0,-5,-3}
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The set of ordered pairs may be an infinite number of points, described by a graph.
Given the following graph, find the domain and range.
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Range = [0,∞) Domain = R
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Example: Domain: {x: x≥5} or [5,∞) Range: {y: y≥0} or [0, ∞)
The set of ordered pairs may be an infinite number of points, described by an algebraic expression. Given the following function, find the domain and range. Example: Domain: {x: x≥5} or [5,∞) Range: {y: y≥0} or [0, ∞)
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Practice: Find the domain and range of the following sets of ordered pairs.
1. {(3,7),(-3,7),(7,-2),(-8,-5),(0,-1)} Domain:{3,-3,7,-8,0} Range:{7,-2,-5,-1}
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2. Domain= [3, ∞) Range: R
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3. Domain={all reals} Range:{y:y≥-4} 4. Domain={x:x≠0} Range:{y:y≠0}
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5. Domain={x: -2≤x≤2} Range:{y: -2≤y≤2} 6. Domain={all reals}
Note: This is NOT a Function! 5. Domain={x: -2≤x≤2} Range:{y: -2≤y≤2} 6. Domain={all reals} Range:{all reals}
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Types Of Relations (including functions)
Chapter 4D
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One – to – One relations A one to one relation exists if, for any x-value, there is a corresponding y-value and vice versa. e.g. [(1,1), (2,2), (3,3), (4,4)]
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One – to – many relations
A one to many relation exists if, for any x-value, there is more than one y-value. But for any y – value there is only one x – value e.g. [(1,1), (1,2), (3,3), (3,4)]
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Many – to – one relations
A many to one relation exists if, for any y-value, there is more than one x-value. But for any x – value there is only one y – value e.g. [(-1,1), (0,1), (1,2)]
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Many – to – many relations
A many to many relation exists if, there is more than one x-value and y – value. e.g. [(0,-1), (0,1), (1,0), (-1,0)]
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Functions One to one or many to one are called functions
Use a vertical line test to test the theory Vertical line cannot intersect the curve/line more than once
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Function Notation Chapter 4F
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What is function notation????
Consider y = 2x The y value is determined by the x values Therefore as a results y is a function of x!!!! This is where simple substitution comes into play (“,)
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f(x) = x2 – 3 f(-2) f(2a) f(x) = x2 – 3 f(1) = (-2)2 – 3 f(1) = 4 – 3
F(2a) = (2a)2 – 3 f(1) = 22 a2 – 3 f(1) = 4a2 – 3
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Full function Notation
A . { (x, y): y = x2 – 4} f : X Y, f(x) = ……. f : R R, f(x) = x2 – 4 B . y = 3x – 4, -2≤ x ≤ 5 f : [-2 , 5] R, f(x) = 3x – 4 C . y = f : R\ {0} R, f(x) = Domain CoDomain Rule
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Special types of Functions ( including hybrid functions)
Chapter 4G
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Recap!! One to one or many to one are called functions
Which we already know!!!
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When x = 0 & x = 3, y = 1 therefore not a 1 to 1 func.
Correct or Wrong Which of the Follwing demonstrates a one to one relationship??? A. {(0, 1), (1, 2), (2, 3), (3, 1)} B . {(2, 3), (3, 5), (4, 7)} C . f(x) = 3x When x = 0 & x = 3, y = 1 therefore not a 1 to 1 func. There is only one y value for each x value therefore this is a 1 to 1 func. From sketching this graph you can clearly see that it is a linear graph therefore this is a 1 to 1 func.
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Restricted functions Restricted functions can be placed on a function through it’s domain. E.g. f(x) = (x + 1)2 We can make the func 1 to one by splitting it into two separate domains: ( -∞, -1] or [-1, ∞)
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Hybrid Functions If sketching by hand I would find x and y intercepts as these two equations represent linear graphs A hybrid function has many different subsets and separate domains. Do worked example 20 with them on the board on page 189.
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Power Functions (hyperbola, truncus and square root functions)
Section 4E page 175
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What we all ready know! The shape of a Quadratic and a Cubic.
What Shape are they when they are +? What shape are they when the equation has a – in front of the x2 or x3? All of the functions that you have leant so far are known as power functions.
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New Power Functions!! When n = -1, f(x) = x-1 this is known as a HYPERBOLA When n = -2, f(x) = x-2 this is known as a TRUNCUS When n = 1/2, f(x) = x1/2 this is known as a Square root func. General Power Function Form: f(x) = a(x – b)n + c
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The Hyberbola
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The Hyberbola The graph shown is called a hyperbola, and is given by the equation y = 1/x This can also be represented as the power function y = x −1. The graph exhibits asymptotic behaviour. That is, as x becomes very large, the graph approaches the x-axis but never touches it. As x becomes very small (approaches 0), the graph approaches the y-axis, but never touches it. So the line x = 0 (the y-axis) is a vertical asymptote, and the line y = 0 (the x-axis) is the horizontal asymptote. Both the domain and the range of the function are all real numbers, except 0; that is, R \ {0}. The graph of y = x −1 can be subject to a number of transformations. Consider y = a(x −b)−1 + c.
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Dilation Factor y = a(x −b)−1 + c.
The value a is a dilation factor. It dilates the graph from the x-axis. For example, the graph of y = compared to the basic graph of y = is shown in the graph on the left.
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Reflection y = − a(x −b)−1 + c.
If a is negative, the graph of the basic hyperbola is reflected in the x-axis. If x is replaced with −x, the graph of the basic hyperbola is reflected in the y-axis. For example, the graphs of y = (x +1)−1 and y = − (x +1)−1 are reflections of each other across the y-axis
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Translation Horizontal Translation
For example, the graph with equation y = (x +1)−1 is a basic hyperbola translated one unit to the left, since b = −1. This graph has a vertical asymptote of x = −1 and domain R \ {−1}, and a horizontal asymptote of y = 0. If a basic hyperbola is translated one unit to the right, it becomes y = (x - 1)−1 , with a vertical asymptote of x = 1 and domain R \ {1}.
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Translation Vertical Translation
The graph with equation y = (x)−1 - 1 is a basic hyperbola translated one unit down. This graph has a horizontal asymptote of y = −1, a range of R \ {−1} and a vertical asymptote of x = 0. If a basic hyperbola is equation y = (x)−1 + 2 translated two units up, it becomes with a horizontal asymptote of y = 2 and a range of R \ {2}.
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Translation Summary (HYPERBOLA)
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When n = -2, f(x) = x-2 this is known as a TRUNCUS
The function is undefined for x = 0. Hence, the equation of the vertical asymptote is x = 0 and the domain of the function is R \{0}. The graph approaches the x-axis very closely but never touches it. So y = 0 is the horizontal asymptote. Since the whole graph of the truncus is above the x-axis, its range is R+ (that is, all positive real numbers). When n = -2, f(x) = x-2 this is known as a TRUNCUS
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Dilation
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Reflection
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Horizontal Translation
Vertical Translation
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Translation Summary (TRUNCUS)
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ON YOUR CAS CALC
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The Square Root Function
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Reflection If a is negative, the graph of a basic square root curve is reflected in the x-axis. The range becomes (−∞, 0]. The domain is still [0, ∞).
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Reflection
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Horizontal Translation
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Vertical Translation
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Translation Summary (Square Root Function)
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On CAS Calc
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