Houghton Mifflin Harcourt Algebra 2, 2015
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Houghton Mifflin Harcourt Algebra 2, 2015 View details
2. Graphing Logarithmic Functions
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Exercise 1 Page 561

To draw the graph of a logarithmic function, we can follow a three-step process.

  1. Identify the base.
  2. Determine points on the graph.
  3. Plot the points and sketch the graph.

Let's do it!

Identifying the Base

Looking at the given functions, we can see that we have a common logarithm and natural logarithm. Recall that the base of the common logarithm is 10, and the natural logarithm has the number e as its base. With this in mind, let's highlight the base of each function. ccc f(x)=log_2x & ⇔ & f(x)=log_()darkorange2x f(x)=log x & ⇔ & f(x)=log_(10) x f(x)=ln x & ⇔ & f(x)=log_e x

Determining Points on the Graph

Using the base b we can identify three points on the graph of a logarithmic function. ( 1b, - 1 ), (1,0), and (b,1) Since we know the bases, we can immediately determine these points.

Function Points
f(x)=log_()darkorange2x ( 12, - 1 ), (1,0), and (2,1)
f(x)=log_(10) x ( 1 10, - 1 ), (1,0), and ( 10,1)
f(x)=log_e x ( 1 e, - 1 ), (1,0), and ( e,1)

Plotting the Points and Sketch the Graph

Finally, we will plot the points and connect them with a smooth curve.

Extra

Useful Theory
The graph depends on the value of the base b. If b>1, the curve increases. If 0