How to indicate that a method was unsuccessful

Question

I have several similar methods, say eg. CalculatePoint(...) and CalculateListOfPoints(...). Occasionally, they may not succeed, and need to indicate this to the caller. For

Answer 1

I would say best practice is a return value means success, and an exception means failure.

I see no reason in the examples you provided that you shouldn't be using exceptions in the event of a failure.