🎯⭐ INTERACTIVE LESSON

Logarithmic Functions and Equations

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Logarithmic Functions and Equations - Complete Interactive Lesson

Part 1: Introduction to Logarithms

📈 Logarithmic Functions

Part 1 of 7 — Logarithm Basics

1. log_b(x) = y means b^y = x

log_b(x) = y means b^y = x

2. Logarithm is the inverse of the exponential function

Logarithm is the inverse of the exponential function

3. Domain

(0, ∞); Range: all real numbers

4. The graph of y = log_b(x) passes through (1, 0) and (b, 1)

The graph of y = log_b(x) passes through (1, 0) and (b, 1)

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Key Concepts Summary

  • log_b(x) = y means b^y = x
  • Logarithm is the inverse of the exponential function
  • Domain: (0, ∞); Range: all real numbers
  • The graph of y = log_b(x) passes through (1, 0) and (b, 1)

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Part 2: Properties of Logarithms

Properties of Logarithms

Part 2 of 7 — Properties of Logarithms

1. Product rule

log_b(MN) = log_b(M) + log_b(N)

2. Quotient rule

log_b(M/N) = log_b(M) - log_b(N)

3. Power rule

log_b(M^n) = n · log_b(M)

4. Change of base

log_b(x) = ln(x)/ln(b) = log(x)/log(b)

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Key Concepts Summary

  • Product rule: log_b(MN) = log_b(M) + log_b(N)
  • Quotient rule: log_b(M/N) = log_b(M) - log_b(N)
  • Power rule: log_b(M^n) = n · log_b(M)
  • Change of base: log_b(x) = ln(x)/ln(b) = log(x)/log(b)

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Part 3: Solving Logarithmic Equations

Common & Natural Logs

Part 3 of 7 — Common & Natural Logs

1. Common log

log(x) = log₁₀(x), used for pH, decibels, Richter scale

2. Natural log

ln(x) = logₑ(x), used in calculus and natural phenomena

3. ln(e) = 1 and log(10) = 1

ln(e) = 1 and log(10) = 1

4. ln(eˣ) = x and e^(ln(x)) = x for x > 0

ln(eˣ) = x and e^(ln(x)) = x for x > 0

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Key Concepts Summary

  • Common log: log(x) = log₁₀(x), used for pH, decibels, Richter scale
  • Natural log: ln(x) = logₑ(x), used in calculus and natural phenomena
  • ln(e) = 1 and log(10) = 1
  • ln(eˣ) = x and e^(ln(x)) = x for x > 0

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Part 4: Change of Base

Solving Logarithmic Equations

Part 4 of 7 — Solving Logarithmic Equations

1. Isolate the logarithmic expression

Isolate the logarithmic expression

2. Convert to exponential form

log_b(x) = y → b^y = x

3. Check for extraneous solutions (argument must be positive)

Check for extraneous solutions (argument must be positive)

4. Use properties to combine or expand log expressions before solving

Use properties to combine or expand log expressions before solving

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Key Concepts Summary

  • Isolate the logarithmic expression
  • Convert to exponential form: log_b(x) = y → b^y = x
  • Check for extraneous solutions (argument must be positive)
  • Use properties to combine or expand log expressions before solving

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Part 5: Logarithmic Models

Logarithmic Modeling

Part 5 of 7 — Logarithmic Modeling

1. Richter scale

M = log(I/I₀), each unit is 10× intensity

2. Decibel scale

dB = 10 · log(I/I₀)

3. pH scale

pH = -log[H⁺], logarithmic measure of acidity

4. Logarithmic regression

y = a + b · ln(x) for data modeling

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Key Concepts Summary

  • Richter scale: M = log(I/I₀), each unit is 10× intensity
  • Decibel scale: dB = 10 · log(I/I₀)
  • pH scale: pH = -log[H⁺], logarithmic measure of acidity
  • Logarithmic regression: y = a + b · ln(x) for data modeling

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Part 6: Problem-Solving Workshop

Problem-Solving Workshop

Part 6 of 7 — Problem-Solving Workshop

1. Richter scale

M = log(I/I₀), each unit is 10× intensity

2. Decibel scale

dB = 10 · log(I/I₀)

3. pH scale

pH = -log[H⁺], logarithmic measure of acidity

4. Logarithmic regression

y = a + b · ln(x) for data modeling

Check Your Understanding 🎯

Key Concepts Summary

  • Richter scale: M = log(I/I₀), each unit is 10× intensity
  • Decibel scale: dB = 10 · log(I/I₀)
  • pH scale: pH = -log[H⁺], logarithmic measure of acidity
  • Logarithmic regression: y = a + b · ln(x) for data modeling

Concept Check 🎯

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Part 7: Review & Applications

Review & Applications

Part 7 of 7 — Review & Applications

1. Richter scale

M = log(I/I₀), each unit is 10× intensity

2. Decibel scale

dB = 10 · log(I/I₀)

3. pH scale

pH = -log[H⁺], logarithmic measure of acidity

4. Logarithmic regression

y = a + b · ln(x) for data modeling

Check Your Understanding 🎯

Key Concepts Summary

  • Richter scale: M = log(I/I₀), each unit is 10× intensity
  • Decibel scale: dB = 10 · log(I/I₀)
  • pH scale: pH = -log[H⁺], logarithmic measure of acidity
  • Logarithmic regression: y = a + b · ln(x) for data modeling

Concept Check 🎯

Match the Concepts 🔍