Linear First Order Differential Equation - Mixture Problem

jdinatale
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The problem and attempt at solution are typed below

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The solution of a linear differential equation as yours is the sum of the general solution of the homogeneous part (dP/dt+0.72P=0) and an arbitrary particular solution of the inhomogeneous equation. That solution can be for which dP/dt=0, that is P=const. Find that constant.
The solution of the homogeneous equation is of the form P=a eλt. Find λ.

ehild
 
ehild said:
The solution of a linear differential equation as yours is the sum of the general solution of the homogeneous part (dP/dt+0.72P=0) and an arbitrary particular solution of the inhomogeneous equation. That solution can be for which dP/dt=0, that is P=const. Find that constant.
The solution of the homogeneous equation is of the form P=a eλt. Find λ.

ehild

Thanks ehild, but I think what would help me is if someone could point out the flaws in my original solution. I'm trying to solve this problem using the method taught in class so I'm hesitant to try something that we haven't learned.

I don't see any mistakes in my work.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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