Linear first-order diffeq system for radioactive decay chain

clynne21
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Homework Statement


Given the followin[Sg decay chain- X→Y→Z
Solve for Nx(t), Ny(t), Nz(t) for the case of Rx(t)=\alphat and assuming Ny(t)=Nz(t)=0

Homework Equations


dNx(t)/dt = -\lambdaxNx(t) + Rx(t)
dNy(t)/dt = -\lambdayNy(t) +\lambdaxNx(t)
dNz(t)/dt = -\lambdazNz(t) +\lambdayNy(t)

The Attempt at a Solution


I know these would be solved with bateman equations and without the Rx(t)=\alphat term I could do these. The production term throws me off and I'm not sure exactly how to go about this.
I have this for Nx(t) = Nx(0)e-\lambdaxt + ∫t0 dt'Rx(t')e\lambdax(t'-t) (the integral is from 0 to t, but the itex wasn't working for me to do that)
So how does Rx(t)=\alphat integrate and where does it go in the other two equations? Thanks!
 
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Excuse me but are you saying that you are trying to solve a system of differential equations but do not know how to integrate \alpha t? The integral of \alpha t with respect to t is \alpha t^2/2. That is usually one of the first integrals you learn.
 
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Haha- no, that's cake LOL

It's really more this term ∫dt'Rx(t')eλx(t'-t) (from 0 to t) that confuses me- I'm not sure where the primes came from and what it is indicating. It was the first step given for a solution. It seemed odd since the αt should be, like you said, extremely simple.
 
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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