Functions - Complete Interactive Lesson
Part 1: Function Notation
๐ Functions Graphs
Part 1 of 7 โ Function Notation & Evaluation
f(x) means "the output of function f when the input is x".
To evaluate f(3): substitute 3 everywhere you see x.
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Key Insight: f(a) = 0 means a is a zero (x-intercept) of the function.
SAT Tip: If f(x) = 2x + 1, then f(3) = 2(3) + 1 = 7.
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Part 2: Interpreting Graphs
Domain and Range
Part 2 of 7 โ Domain and Range
Domain: all possible input (x) values.
Range: all possible output (y) values.
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Key Insight: Restrictions: no division by zero, no square root of negatives (for reals).
SAT Tip: From a graph: domain is the horizontal extent, range is the vertical extent.
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Part 3: Domain & Range
Interpreting Graphs
Part 3 of 7 โ Interpreting Graphs
Increasing: graph goes up left to right; decreasing: goes down.
Maximum/minimum: highest/lowest point on the graph.
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Key Insight: Intercepts: where the graph crosses the axes.
SAT Tip: Rate of change = (change in y)/(change in x) = slope between two points.
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Part 4: Transformations
Transformations of Functions
Part 4 of 7 โ Transformations of Functions
f(x) + k: shifts up k units; f(x) - k: shifts down k.
f(x - h): shifts right h units; f(x + h): shifts left h.
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Key Insight: af(x): vertical stretch (a > 1) or compression (0 < a < 1).
SAT Tip: f(-x): reflects over y-axis; -f(x): reflects over x-axis.
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Part 5: Function Composition
Function Composition
Part 5 of 7 โ Function Composition
(f โ g)(x) = f(g(x)): apply g first, then f.
Find g(x) first, then use that result as input to f.
Check Your Understanding ๐ฏ
Key Insight: Domain of f โ g: x must be in domain of g, AND g(x) must be in domain of f.
SAT Tip: Example: f(x) = xยฒ, g(x) = x + 1, then f(g(x)) = (x+1)ยฒ.
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Part 6: Problem-Solving Workshop
Problem-Solving Workshop
Part 6 of 7 โ Problem-Solving Workshop
(f โ g)(x) = f(g(x)): apply g first, then f.
Find g(x) first, then use that result as input to f.
Check Your Understanding ๐ฏ
Key Insight: Domain of f โ g: x must be in domain of g, AND g(x) must be in domain of f.
SAT Tip: Example: f(x) = xยฒ, g(x) = x + 1, then f(g(x)) = (x+1)ยฒ.
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Part 7: Review & Applications
Review & Applications
Part 7 of 7 โ Review & Applications
(f โ g)(x) = f(g(x)): apply g first, then f.
Find g(x) first, then use that result as input to f.
Check Your Understanding ๐ฏ
Key Insight: Domain of f โ g: x must be in domain of g, AND g(x) must be in domain of f.
SAT Tip: Example: f(x) = xยฒ, g(x) = x + 1, then f(g(x)) = (x+1)ยฒ.
Check Your Understanding ๐ฏ
Match the Concepts ๐