..Hi,

I've been taught that when integration involves logs like , you must express your answer as the log of an absolute value unless that value is known to be positive. e.g. in this case .

But in my textbook, it rarely uses absolute values, and just states the answers in the form , which then obviously changes the solutions to many differential equations.

Am I right to use the absolute value, or am I missing something? Mr F says: You are right.

Thanks for your help