Determining the Key Features of Function Graphs
The Key Features of Function Graphs - Preview Domain and Range x-intercepts and y-intercepts Intervals of increasing, decreasing, and constant behavior Parent Equations Maxima and Minima
Domain Domain is the set of all possible input or x-values To find the domain of the graph we look at the x-axis of the graph
Determining Domain - Symbols Open Circle → Exclusive ( ) Closed Circle → Inclusive [ ]
Identifying the Domain Start at the far left of the graph. Move along the x-axis until you find the lowest possible x-value of the graph. This is your lower bound. Note if you have a open circle or a closed circle. Keep moving along the x-axis until you find your highest possible x-value of the graph. This is your upper bound. Note if you have a open circle or a closed circle.
Examples Domain: Domain:
Example Domain:
Determining Domain - Infinity
Examples Domain: Domain:
Your Turn: Complete problems 3, 7, and find the domain of 9 and 10 on pg. 160 from the Xeroxed sheets 3. 7. 9. 10.
Range The set of all possible output or y-values To find the range of the graph we look at the y-axis of the graph We also use open and closed circles for the range
Identifying the Range Start at the far left of the graph. Move along the x-axis until you find the lowest possible x-value of the graph. This is your lower bound. Note if you have a open circle or a closed circle. Keep moving along the x-axis until you find your highest possible x-value of the graph. This is your upper bound. Note if you have a open circle or a closed circle.
Examples Range: Range:
Examples Range: Range:
Your Turn: Complete problems 4, 8, and find the range of 9 and 10 on pg. 160 from the Xeroxed sheets 4. 8. 9. 10.
X-Intercepts Where the graph crosses the x-axis Has many names: Roots Zeros
Examples x-intercepts: x-intercepts:
Y-Intercepts Where the graph crosses the y-axis y-intercepts:
Seek and Solve!!!
Types of Function Behavior Increasing Decreasing Constant When determining the type of behavior, we always move from left to right on the graph
Roller Coasters!!! Fujiyama in Japan
Types of Behavior – Increasing As x increases, y also increases Direct Relationship
Types of Behavior – Constant As x increases, y stays the same
Types of Behavior – Decreasing As x increases, y decreases Inverse Relationship
Identifying Intervals of Behavior We use interval notation The interval measures x-values. The type of behavior describes y-values. Increasing: [0, 4) The y-values are increasing the x-values are between 0 inclusive and 4 exclusive when
Identifying Intervals of Behavior Increasing: Constant: Decreasing: x 1 1
Identifying Intervals of Behavior, cont. Increasing: Constant: Decreasing: x -3 -1 Don’t get distracted by the arrows! Even though both of the arrows point “up”, the graph isn’t increasing at both ends of the graph!
Your Turn: Complete problems 1 – 4 on The Key Features of Function Graphs – Part II handout.
1. 2. 3. 4.
What do you think of when you hear the word parent?
Parent Function The most basic form of a type of function Determines the general shape of the graph
Basic Types of Parent Functions Linear Absolute Value Greatest Integer Quadratic Cubic Square Root Cube Root Reciprocal
Parent Function Flipbook
Function Name: Linear Parent Function: f(x) = x “Baby” Functions: y 2
Greatest Integer Function f(x) = [[x]] f(x) = int(x) Rounding function Always round down
“Baby” Functions Look and behave similarly to their parent functions To get a “baby” functions, add, subtract, multiply, and/or divide parent equations by (generally) constants f(x) = x2 f(x) = 5x2 – 14 f(x) = f(x) = f(x) = x3 f(x) = -2x3 + 4x2 – x + 2
“Baby” Functions, cont. f(x) = |x|
Your Turn: Create your own “baby” functions in your parent functions book.
Identifying Parent Functions From Equations: Identify the most important operation Special Operation (absolute value, greatest integer) Division by x Highest Exponent (this includes square roots and cube roots)
Examples f(x) = x3 + 4x – 3 f(x) = -2| x | + 11
Identifying Parent Equations From Graphs: Try to match graphs to the closest parent function graph
Examples
Your Turn: Complete problems 5 – 12 on The Key Features of Function Graphs handout
Maximum (Maxima) and Minimum (Minima) Points Peaks (or hills) are your maximum points Valleys are your minimum points
Identifying Minimum and Maximum Points Write the answers as points You can have any combination of min and max points Minimum: Maximum:
Examples
Your Turn: Complete problems 1 – 6 on The Key Features of Function Graphs – Part III handout.
1. 2. 3. 4. 5. 6.
Reminder: Find f(#) and Find f(x) = x Find the value of f(x) when x equals #. Solve for f(x) or y! Find f(x) = # Find the value of x when f(x) equals #. Solve for x!
Evaluating Graphs of Functions – Find f(#) Draw a (vertical) line at x = # The intersection points are points where the graph = f(#) f(1) = f(–2) =
Evaluating Graphs of Functions – Find f(x) = # Draw a (horizontal) line at y = # The intersection points are points where the graph is f(x) = # f(x) = –2 f(x) = 2
Example Find f(1) Find f(–0.5) Find f(x) = 0 Find f(x) = –5
Your Turn: Complete Parts A – D for problems 7 – 14 on The Key Features of Function Graphs – Part III handout.
7. 8. 9. 10.
11. 12. 13. 14.