Variations of a parameter in a differential equation

themagiciant95
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Homework Statement
I have this differential equation:

[tex]a_{1}\dot{y}(t)+y(t)=b_{0}u(t)+b_{1}\dot{u}(t)[/tex]

and my prof, during a lesson, said that from this equation it's possible to derive that:

[tex]\Delta y(t)=-\Delta a_{1}\dot{y}(t)[/tex]
Relevant Equations
(Homework Equations are already stated)
I tried to derive this by myself but I'm stuck. What i did it to substitute a_{1} with a_{1} +\Delta a_{1} in the first equation, getting:

(a_{1}+\Delta a_{1})\dot{y}(t)+y(t)=b_{0}u(t)+b_{1}\dot{u}(t)

and trying to subtract a_{1}\dot{y}(t)+y(t)=b_{0}u(t)+b_{1}\dot{u}(t) to it. But it's not the right way. Can you help me ?

Ps: i think i have to make the assumption the input u(t) remains the same, right?
 
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I must admit, it looks a bit random to me. Are ##a_1, b_0, b_1## constants?

Are you sure it doesn't relate to the homogeneous equation?
 
Yes, let's suppose that its a real system with the parameters a_{1},b_{0}, b_{1}, output y(t) and input x(t) and \Delta a_{1},\Delta b_{0},\Delta b_{1} are faults the parameters
 
themagiciant95 said:
Yes, let's suppose that its a real system with the parameters a_{1},b_{0}, b_{1} and \Delta a_{1},\Delta b_{0},\Delta b_{1} are faults on this parameters

In general, I can't say it makes much sense to me. There must be something in the context of the lecture.
 
My prof also said to conjecture that the parameters change really slowly
 
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