II. Setting a Window  Finding One That Works
B. Examples
2. Trigonometric Function Examples
ZTRIG is a preset window with [xMin,xMax] =[8.24668071567, 8.24668071567], [yMin, yMax]=[4,4], xScl= . This window will work for many trig functions. However, some trig functions will not work in the preset, and you will need to set a new window. You must be careful of the MODE. Most of the time you should set the MODE to Radian measure.
i) Example 1: Graph the function shown in the first window.
Enter the function.

Use ZTRIG.

ii) Example 2: Graph the function . The asymptotes must be taken into consideration. So, for this function, try the ZTRIG window first. You can see that in the graph, the calculator has drawn what appears to be an asymptote. This is not an asymptote. What has happened is that the calculator has tried to connect the dots, and the line is the result. There is a way to avoid this using STYLE which is covered in the y(x) menu.
Enter the function.

Use ZTrig.

iii) Example 3: Graph the function . Notice that the 2 remains in the numerator. Since the period is small, the ZTRIG menu shows too many periods and you have what appears to be vertical lines. These "vertical lines" are actually the result of the calculator trying to connect the maximum and minimum values. These can be ignored or you can use dot mode which is discussed in the y(x) menu. Once you have looked at it in ZTRIG, then you can modify the widow.
Enter the
function. 
Start with ZTRIG
and then modify. 
Use these values
to set the window. 
This is a
better view. 