Particular Integral of Exponential

madman01
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First-Order Linear System Transient Response

Hey there,

I am trying to solve a problem of first order equation which is

A temperature sensor has a first order response with τ = 18 seconds. The calibration curve of the sensor is presented in Figure 1. Graph the sensor response when it is exposed to the temperature profile shown in Figure 2. Present the senor voltage as a function of time. Sensor has been kept at 15 °C for a long time before the operation.

Homework Statement



\taudy(t)/dt + y(t) = K
Figure 1 & 2 are attached

Homework Equations



where \tau =18 and K is given by an equation 5+t/3 (deduce from figure 1)

The Attempt at a Solution



I know that first order equation’s answer is the addition of two general solutions: homogenous (natural response of the equation) and particular-integral (generated by the step function there

T(total) = T(homogenous) + T(particular-integral)
T(homogenous)= Ae^-t/5
T(particular-integral)= I am not sure how to do the integral of Ae^-t/5 ... Any Idea's

So if someone can help me with the T(particular-integral) then i would be able to find the value of A by putting the initial condition of T(0)=5V
 

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  • Figure 1 & 2.jpg
    Figure 1 & 2.jpg
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You could assume that a particular solution is at + b. Substitute this into the equation and solve for a and b.
 
Hint: divide both sides by tau. If you have studied ODE's, this hint should be enough.
 
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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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