Hey guys I have a few questions... My book defines the Heisenberg uncertainty principle by ∆x∆Px >= aitch-bar All other resources I have have it stated as ∆x∆Px >= aitch-bar/2. They mention that ∆Px and ∆x represent the rms values of independent measurements. My book represents ∆x and ∆Px as the standard-deviation uncertanties right.. So say for instance you get a general question like x-cordinate of a proton is measured with uncertainty of 1.3mm. What is the xcomponent of velocity to the minimum percentage of uncertainty of 33%. would you take ∆x as the standard deviation uncertanties or rms values ? It seems like it varies from book to book but in general shouldnt this be the same? Say someone posed a question like this online, how would I know what to use?