ACT Math
Lesson Plan
Exponential growth and decay
Goals / Objectives
Build $y = ab^x$ from a described situation, identifying $a$ as the initial value and $b$ as the per-step factor, and evaluate it to answer the question asked
Distinguish a constant-difference (linear) pattern from a constant-factor (exponential) pattern by computing successive ratios, and extend a constant-factor pattern by a few terms
Convert a percentage rate to a growth or decay factor using $b = 1 + r$ or $b = 1 - r$, and a factor back to a percentage rate
Classify a given exponential function as growth or decay from the value of $b$, and explain why a decaying exponential never reaches zero
Standards
F 702. Build functions for relations that are exponential F 301. Extend a given pattern by a few terms for patterns that have a constant factor between terms — score range 16-19, lines 141-143 N 605. Apply properties of rational exponents — score range 28-32, line 73 A 512. Work problems involving positive integer exponents — score range 24-27, lines 253-254
Academic Vocabulary
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Enrichment
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Anticipatory Set / Bell Work
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Modeling
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Homework
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