Differential Equations
Chapter 1.9
Interpreting a mixing problem and solving it using the method of integrating factors.
Suppose a 200-gallon tank originally has 100 gallons of salt water in it at a concentration of 1 gram of salt per gallon. We start to pour in 5 gallons of salt water per minute having a concentration of 2 grams of salt per gallon. Meanwhile, we let out 3 gallons of well-mixed water per minute. What is the concentration of salt when the tank is full?
Errata:
5:04, should read "100+2t" not "100-2t"
7:59, u-substitution, not integration by parts
