II. Setting a Window - Finding One That Works

B. Examples

6. Logarithmic Function Examples

Logarithmic functions will usually have a vertical asymptote, and the domain must be considered.

i) Example 1: Graph the function . There will be a vertical asymptote at x=-3, and the domain is . Therefore, you will not be concerned with values of x less than -3. Consider this when you determine a window. It appears that the graph just stops, but it does not. The reason it has this appearance is because of the pixels.

Enter the function.
Use ZOOM4

ii) Example 2: Graph the function . Since the domain is all real numbers, there is no vertical asymptote and ZOOM6 is a good window.

Enter the
function.
Use ZOOM6.

 

iii) Example 3: 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 TABLE to find values and set the table shown.

Enter the
function.
Set the window.
Graph the
function.