II. Setting Windows and Styles

B. Examples

6. Logarithmic Functions

Logarithmic functions usually have a restricted domain and a vertical asymptote. This should be considered when you set your window.

i) Example: Graph the function . The domain is , and there will be a vertical asymptote of x=-3. Therefore, you will not be concerned with values of x less than -3. Consider this when you determine your window. It appears that the graph just stops, but it does not. The reason it has this appearance is because of the pixels. You can find the log function using the catalog.

Enter the function.
Use ZoomDec.

ii) Example: Graph the function . Since the domain is all real numbers, there is no vertical asymptote and ZoomStd is a good window.

Enter the function.
Use ZoomStd.

iii) Example: Graph the function . To enter this function, you must use the Change of Base Formula. There will be a vertical asymptote of x=2. Use the TABLE to find values, and set the window shown.

Enter the function.
Set a Window.
Graph.

 

 

Polynomial
Trigonometry
Rational
Exponential
Radical
Logarithms
I. Entering
Graphs
II. Windows
& Styles
III. Working
with Graphs
IV. Special
Graphs
V. Other
Graph Modes