You can use GeoGebra to find the domain and range of a function. 
     GeoGebra Instruction 1
Algebra     View     and         Graphics     View     under         View     in         Menu.         Algebra     View.         Intersect Min command by typing         Min(<Function>, <Start x-Value>, <End x-Value>)
in Algebra View.         
Enter the name of your function (,         ,         )         in <Function>. For <Start>, enter the lower endpoint of the domain. For <End>,         enter the upper endpoint of the domain.         
Do the same as above with the command
Max(<Function>, <Start x-Value>, <End x-Value>)
in Algebra View.         
If your domain is a union of several intervals, repeat these two commands for all the intervals.
The lower endpoint of the range is the -value of the lowest point on the graph within the domain.
The upper endpoint of the range is the -value of the highest point on the graph within the domain.