You can use GeoGebra to compute the limit of function as the variable tends towards a certain value. 
     GeoGebra Instruction 1
Open Algebra View under  
View in  
Menu. 
To find the regular two-sided limit of <Function> as the variable approaches         <Value>, use the command  
Limit(<Function>, <Value>)
To find the left-handed limit, use the command
LimitBelow(<Function>, <Value>)
To find the right-handed limit, use the command
LimitAbove(<Function>, <Value>)