title: c# how to check if a number is infinity
body: <p>i have a little problem. I have two double variables which each has the value 1*10^250. Now if I multiplicate these two values I get a result which is also a double variable. The problem is that the result of the multiplication gives me the value infinity but I want to prevent this and give an error message. So it would be nice if someone know how to identify if a number is infinity.</p>