Date: Jan 5, 2013 1:08 AM
Author: William Elliot
Subject: Re: Off Topic Physics/math question

On Fri, 4 Jan 2013, wrschlanger@gmail.com wrote:

> If y(x) = 1 / x
> then y(x) > 0 when x > 0 and y(x) < 0 when x < 0.
> 
> According to the power rule of Calculus, y'(x) = -1 / x^2.
> So y'(x) is always negative.
> 
> Are we losing information by taking the derivative?

Yes, f(x) = 1/x + c has the same derivative.