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#1 Help Me ! » anybody please help me!!! » 2008-03-19 19:08:22

frem
Replies: 1

Please help me to solve the below modelling differential equation question:
A large tank is filled to capacity with 500 gallons of pure water. Brine containing 2 pounds of salt per gallon is pumped into the tank at a rate 0f 5 gal/min. The well mixed solution is pumped out at the rate of 10 gal/min. When is the tank empty?

#2 Help Me ! » non- exact equation. » 2008-02-25 21:25:26

frem
Replies: 1

Please somebody show me how to find the integrating factor of this non- exact equation:
(10-6y+e^-3x)dx - 2 dy = 0
It's a pleasure if you show step by step. Thanks.

#3 Help Me ! » confusing... » 2008-02-25 05:21:14

frem
Replies: 1

I've answered an exact equation. The question is:
(x-y³ +y² sinx) dx = (3xy²+2y cosx) dy = 0.
In the end, I got (x²/2)-y²  cosx - y³x=C but the answer in the answer sheet is opposite sign to my answer. Does my answer can be accepted?

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