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Logarithmic Functions and Graphs. Objective. Sketch Logarithmic Graphs Use Log Properties. Relevance. Log functions are useful for modeling data that represent quantities that increase or decrease slowly .
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Objective Sketch Logarithmic Graphs Use Log Properties
Relevance Log functions are useful for modeling data that represent quantities that increase or decrease slowly. For example, a log function can model the minimum required ventilation rates in public school classrooms.
Warm Up - If $5,000 is invested at an interest rate of 5% per year, find the amount of the investment at the end of 5 years for the following compounding methods: • Annually • Monthly • Quarterly • Continuously
Annually: Monthly:
Quarterly: Continuously
Warm Up Solve: Find the Vertex:
Logarithmic Function • It’s the inverse of the exponential function Switch the x’s and the y’s!
Logarithmic Function Used to find unknown exponents in exponential models. Logs define many measurement scales in the sciences: 1) ph 2) decibal 3) Richter scale
For any positive base b, where b≠1: bx = y if and only if x = logby Exponential Form Logarithmic Form
Graph: Is the inverse of Domain: Range: Domain: Range:
Graph: Up 3 from previous example! Domain: Range:
Graph: Left 4 from Original Example! Domain: Range:
Graph: Right 2 from Original Example! Domain: Range:
Graph: Reflected over y-axis. Domain: Range:
Graph: Reflected over x-axis. Domain: Range:
The Natural Logarithmic Function • The natural logarithmic function is the inverse of the natural exponential function