I am using Wolfram Alpha on my laptop and I could do a few problems then suddenly my computer started to freeze and any effort to get off the page or exit the browser did not do anything. I am using a 2012 Apple MacBook Pro running Mountain Lion OSx 10.8.5. There's a possibility that it could be my computer, but I haven't had any problems with it thus far until I started to integrate on wolfram alpha. Anyone else had this problem before?