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Grade 11 Precalculus · Lesson 2.2
Graphs of Functions
Explanation01Recognize before you sketch
Graphing Toolkit · Start from the Family
Recognize before you sketch
Graphing Toolkit · Start from the Family
Start by reconnecting equations with familiar graph shapes. Before plotting many points, identify the family and the information that controls its shape.
Linear · slope 2 · y-intercept −1
Quadratic · vertex (0,0)
Quadratic · vertex (2,3)
Quadratic · standard form; find key points
Absolute value · V-shape · vertex (2,3)
Verify · Translated Quadratic
Exact mathematical models; sampled curves use independent x/y scales. Toggle an equation to show or hide it.
Optional Desmos exploration
The native graph and checks work without this external service.
Explanation02Compare shapes
Power Functions · Even, Odd, and the Effect of n
Compare shapes
Power Functions · Even, Odd, and the Effect of n
Power Function Explorer
Rule: y = x2. Landmarks: (−1, 1), (0, 0), (1, 1).
As n increases, the graph becomes flatter near zero and steeper when |x| > 1. Both axes use the same unit length.
Desmos · Power Family Comparison
Exact mathematical models; sampled curves use independent x/y scales. Toggle an equation to show or hide it.
Optional Desmos exploration
The native graph and checks work without this external service.
Explanation03One function · different rules
Piecewise Functions · Choose the Interval First
One function · different rules
Piecewise Functions · Choose the Interval First
Piecewise endpoint decisions
Compare the boundary with its neighbors: −0.5, 0, 0.5 and 2.5, 3, 3.5.
Final graph
Completed graph · three pieces
Final graph
Completed graph · absolute value and root pieces
Explanation04Find the breaking point
Absolute Value → Piecewise
Find the breaking point
Absolute Value → Piecewise
The central routine is to find where the expression inside the absolute value changes sign. Solve the inside equal to zero, split the number line there, then remove the absolute value with the correct sign.
Final graph
Completed graph · f(x)=|x|
Final graph
Completed graph · f(x)=|x−3|
Final graph
Completed graph · f(x)=|1−x|
Practice
Find all breaking point(s), make sign intervals, then write the piecewise rule.
Practice
Find all breaking point(s), make sign intervals, then write the piecewise rule.
Challenge
Find all breaking point(s), make sign intervals, then write the piecewise rule.
Challenge
Find all breaking point(s), make sign intervals, then write the piecewise rule.
Explanation05Reverse the process
Graph → Equation
Reverse the process
Graph → Equation
When a graph is given, identify the family first. For an absolute-value graph, read the vertex and use another point to determine the vertical scale.
Vertex → substitute one more point → solve for .
- Given graph
Explanation06Step by step
Greatest Integer Functions
Step by step
Greatest Integer Functions
Greatest Integer Step Explorer
The output k satisfies k ≤ x < k + 1. At an integer, the output is that integer itself.
Mr. Azzam’s graphing routine
- Find the subinterval length from the coefficient of x.
- Start subintervals from the zeros/boundaries of the inside expression.
- Place equality on the correct endpoint according to the direction of the x coefficient.
- Substitute the included endpoint to find the constant value on each step.
Final graph
Completed graph · floor(x+2)
Final graph
Completed graph · wider steps
Final graph
Completed graph · negative coefficient on restricted domain
Explanation07A visual decision
Vertical Line Test
A visual decision
Vertical Line Test
Vertical Line Test Lab
Solid: relation. Dashed: test line. Window only; parabolas continue beyond it. Circle radius 2.5. Equal axis units.
y = x²/4 − 2
A graph represents y as a function of x if and only if no vertical line intersects the graph more than once.
Explanation08Algebra can decide too
Does an Equation Define y as a Function of x?
Algebra can decide too
Does an Equation Define y as a Function of x?
Solve for . The question is whether each allowed x produces exactly one y-value.
Key takeaway09Connect everything
Exam Strategy · Analyze → Plot → Sketch → Verify
Connect everything
Exam Strategy · Analyze → Plot → Sketch → Verify
Identify the family, restrictions, breakpoints, vertex, or step width.
Plot the controlling points/endpoints, then complete the actual graph. A graphing question is not finished before the graph.
Use key points, endpoints, restrictions and Desmos verification to check—not replace—your hand-built graph.
Lesson Mastery Checkpoint
Rate each skill. This is only the starting signal; your actual Practice and Assessment performance will update the plan.
Graph families & power functions
Piecewise graphs & endpoints
Absolute value ↔ piecewise
Graph → equation
Greatest integer functions
Vertical line test
Equation → function or not