Physics thermodynamics equation

1. Jan 14, 2009

proace360

1. The problem statement, all variables and given/known data
A certain amount of a monatomic ideal gas undergoes the process shown in the figure below, in which its pressure doubles and its volume triples.

In terms of the number of moles, n, the initial pressure, Pi, and the initial volume, Vi, determine the quantities tabulated below. Use n, Pi, and Vi to represent n, Pi, and Vi, respectively.

(a) work W done by the gas
(b) change in the internal energy U of the gas
(c) heat Q added to the gas

2. Relevant equations

W=integral of graph... lol
T=PV/nR
Change in Eint=(3/2)nRT

3. The attempt at a solution

ok i worked out (a) to be 3(Vi)(Pi) by finding the integral (area under the graph) and (b) to be (15/2)(Pi)(Vi) by finding the difference in temperatures and putting them in the energy equation (having the R value and n value cancel out). I'm fairly certain im correct, but webassign says that they are wrong. The only reason I can think of why is because webassign treats the (Pi) as the greek Pi 3.14159 number, but ive been entering it the way it says.

Can someone confirm this with me/tell me why its treating it as pi?

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2. Jan 14, 2009

proace360

nvm i had to put P_i and not Pi lol