Mathematics - Algebra & Differential Calculus

[quote=doof]i found a mistake in mine. salt in is .4 x 20, not 4. x 10 as i had it written down. now im getting an 2/5 which is closer to their 3/4[/quote]

[quote=jhoijhoi]I have a different formula too, will bring it to the lecture. Will you be at the lecture today? It's a bit late to ask, lol. I'm planning on sitting next to some people and just asking them what they got, to see if we're on the right track. If you do the same... we can collaborate on things that we got wrong/right ^^ Hmm, well, we can meet up sometime today if you'd like, or maybe we can meet up before the lecture tomorrow and compare notes ^^[/quote]

[quote=jhoijhoi]I am getting 0.297 as my final concentration. Want to meet up before our lecture tomorrow, outside or something?[/quote]

[quote=doof]hey, sorry for the late reply. i worked all day today. see how we go tonight.[/quote]

[quote=doof]0.297 i dont think can be correct. the solution gains mass. The intial value is 8grams. The maximum it can be is 200L x .4 = 80g[/quote]

[quote=jhoijhoi]This is what I had: Vo = Initial Volume Vf = Final Volume Q1 = Flow in Q2 = Flow out Qf = Final Concentration Mf = Mass final Mo = Mass initial t = Time dv/dt = Q1 - Q2 I Q1 - Q2 = Q1t-Q2t + Vo Vf = t(Q1-Q2) + Vo dm/dt = C1Q1 - C2Q2 I C1Q1 - C2Q2 Mf = t(C1Q1 - C2Q2) + Mo C2 = (Mf)/[Vo + t(Q1 - Q2)] Cf = Mf/Vf Cf = (Mo + C1Q1t)/(Vo + Q1t) :. Vf = t(Q1 - Q2) + Vo t = 10 minutes :. Cf = (10 + 0.1(20)10)/(100 + 0.1(10)) Cf = 30/101 = 0.297[/quote]

[quote=doof]I just got 30g. I think im going with this answer. happy to get you to confirm if you like.[/quote]

[quote=doof]Where is your integrating factor and gen solution?[/quote]

[quote=jhoijhoi]dv/dt = Q1 - Q2 I Q1 - Q2 = Q1t-Q2t + Vo Vf = t(Q1-Q2) + Vo dm/dt = C1Q1 - C2Q2 I C1Q1 - C2Q2 Mf = t(C1Q1 - C2Q2) + Mo I = Integration. Couldn't figure out how to get C(t), so went with Mass, as C is reliant on Mass anyway. What did you do?[/quote]

[quote=jhoijhoi]In case anyone was interested, these were the answers: [IMG]http://i1106.photobucket.com/albums/h380/thejhoijhoi/sddsasdadsasdsadasdsadsdaasdddddddddddddddddddddddddddddddddddd.png[/IMG][/quote]