1. The problem statement, all variables and given/known data 1. Is (∂P/∂x)(∂x/∂P) = 1? I realized that's not true, but i'm not sure why. 2. Say we have an equation PV = T*exp(VT) The question wanted to find (∂P/∂V), (∂V/∂T) and (∂T/∂P) and show that product of all 3 = -1. 3. The attempt at a solution I tried moving the variables about then differentiate but I got all the wrong answers, for example: V = (T/P) * exp (VT) then to find (∂V/∂T) with P constant, i did product rule.. which gave me wrong answers T = PV * exp(-VT) then to find (∂T/∂P) with V constant, i use product rule again..which completely gave me the wrong answers.. So I thought that you're not allowed to move the variables around? Strangely I got (∂P/∂V) correct despite moving the variables around... coincidence?