A little confused in Zero Input response

In summary, the conversation discusses the solution of a complex problem involving roots and zero input response. The given equation is (D-1)(D2+1)y(t)=(D2+2)f(t) with initial conditions of y(0)=4, y'(0)=3, and y''(0)=3. The roots are identified as +1, j, and -j, but the use of j and their identity is not clear. The individual is seeking step-by-step help to better understand the concept.
  • #1
zee3b
7
0
Guys I know how to solve the simple ones but this one has complex roots
I have to find the zero input response

(D-1)(D2+1)y(t)=(D2+2)f(t)

y(0)=4 y'(0)=3 y''(0)=3

D2= D square. Y' = first derivative Y''= secondI know the roots are +1, j and -j

But I don't know how to solve or use the j's and their identity

I maybe wrong. If it wasn't for the square inside the parenthesis I would be able to solve it.

Any help would be appreciated. (step by step so i can understand it better) once again I know the whole concept but not the j's
 
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  • #2
Any one? :(
 
  • #3
The zero input response refers to the output of a system when there is no input (or forcing function) acting on it. In this case, the system is described by the differential equation (D-1)(D2+1)y(t)=(D2+2)f(t), where D represents the derivative operator.

To find the zero input response, we can use the initial conditions given: y(0)=4, y'(0)=3, and y''(0)=3. These initial conditions represent the state of the system at t=0, before any input is applied.

To solve this differential equation, we first need to find the characteristic equation. This is done by setting the coefficients of the highest derivative term to zero, which in this case is D2+1=0. This gives us the characteristic equation D2+1=0, which has roots of ±j (where j is the imaginary unit, equal to √-1).

Next, we can use the roots of the characteristic equation to find the general solution of the differential equation. This is done by using the formula y(t)=C1e^(r1t)+C2e^(r2t), where r1 and r2 are the roots of the characteristic equation and C1 and C2 are constants to be determined. In this case, the general solution is y(t)=C1e^(jt)+C2e^(-jt).

To find the specific values of C1 and C2, we can use the initial conditions given. Plugging in t=0, we get y(0)=C1+C2=4. Plugging in t=0 for the first derivative, we get y'(0)=jC1-jC2=3. And plugging in t=0 for the second derivative, we get y''(0)=-C1-C2=3. This gives us a system of equations that we can solve to find the values of C1 and C2.

Using these values, we can then find the zero input response by plugging the general solution back into the original differential equation. This gives us the final solution of y(t)=4cos(t)+3sin(t).

In summary, to find the zero input response in this case, we first needed to find the characteristic equation and its roots. Then, we used the initial conditions to find the general solution and determined the specific values of the constants. Finally, we plugged
 

FAQ: A little confused in Zero Input response

What is the concept of "Zero Input Response" in scientific terms?

The "Zero Input Response" refers to the output of a system when there is no external input or force acting on it. In other words, it is the response of the system due to its internal dynamics or initial conditions.

How is "Zero Input Response" different from "Zero State Response"?

The "Zero Input Response" is the response of a system when there is no external input, while the "Zero State Response" is the response of a system when there is no initial condition or energy stored in the system. In other words, the "Zero State Response" only considers the effect of external inputs, while the "Zero Input Response" only considers the internal dynamics of the system.

Can the "Zero Input Response" be used to analyze the stability of a system?

Yes, the "Zero Input Response" can be used to analyze the stability of a system as it provides information about the behavior of the system without any external input. The stability of a system can be determined by analyzing the frequency response and time-domain characteristics of the "Zero Input Response."

What are the factors that affect the "Zero Input Response" of a system?

The "Zero Input Response" of a system is affected by the system's initial conditions, such as the values of its state variables, and the system's internal dynamics, such as its transfer function. Other factors that may affect the "Zero Input Response" include the type of system, its complexity, and external disturbances.

How is the "Zero Input Response" used in practical applications?

The "Zero Input Response" is commonly used in the analysis and design of control systems to understand the behavior of the system without any external input. It is also used to assess the stability and performance of a system and to determine the appropriate control parameters that can help achieve the desired response. Additionally, the "Zero Input Response" is used in signal processing and filtering applications to eliminate unwanted noise and disturbances from a system.

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