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Hi guys
Got this question that I'm a little stuck on...Its to do with volume of a drug flowing in and flowing out of a patients blood...I've narrowed it down to the following integration but then I get stuck...
dr/dt = a1 + a2*sin(k1*t) - r/v1
where,
r = volume of drug
t= time
a1, a2, k1 and v1 are all constant
how can i split the variables? i can't take the r/v1 to the LHS because when i multiply through by dt, I get an extra term rdt/v1 on the LHS that I don't want...
lecturer gave a clue that I have to integrate by parts twice??? really confuzzled...need your help
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I may have messed up on the way so here is the full problem...
"The drug is removed by the patient's kidneys a rate which is proportional to the concentration of the drug in the patients blood..."
From this i thought...Rate Out = k * conc. of drug
and conc. of drug is r/v1 where r (as above) is the mg of drug in the blood and v1 is the constant ammount of blood in the body
so Rate Out = k * r/v1 ...is this the right thinking?
and dr/dt = Rate in - Rate out...using the rate out k*r/v1 and the rate in given in the question below
Rest of question...
"Derive a differential equation describing the dependence on time of the drug concentration in the patient's blood. You can assume the volume of the patient's blood is a constant and that the rate of drug addition per unit volume of blood is a1 + a2*sin(k1*t) where a1, a2 and k1 are constants and t is time."
The rest of the questions gives values and asks to plug them in etc which is straight forward...just stuck on integrating the diff. equation and whether or not I even have the correct diff. equation in the first place...
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no worries, solved it
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