What is difference between necessary and sufficient condition?

What is difference between necessary and sufficient condition?

A necessary condition is a condition that must be present for an event to occur. A sufficient condition is a condition or set of conditions that will produce the event. A necessary condition must be there, but it alone does not provide sufficient cause for the occurrence of the event.

What does sufficient mean in logic?

In logic and mathematics, necessity and sufficiency are terms used to describe a conditional or implicational relationship between two statements. The assertion that a statement is a “necessary and sufficient” condition of another means that the former statement is true if and only if the latter is true.

What is a sufficient cause?

Rothman defined a sufficient cause as “…a complete causal mechanism” that “inevitably produces disease.” Consequently, a “sufficient cause” is not a single factor, but a minimum set of factors and circumstances that, if present in a given individual, will produce the disease.

What is sufficient condition in math?

In mathematics, a condition that must be satisfied for a statement to be true and without which the statement cannot be true. (Compare necessary condition.) …

How do you know if a system is BIBO stable?

A system is BIBO stable if every bounded input signal results in a bounded output signal, where boundedness is the property that the absolute value of a signal does not exceed some finite constant.

What is an example of a stable system?

An example of a stable system is a hammock. I was able to determine whether or not a hammock is a stable system because when a person is laying on it, it will swing. But once the person gets off, the hammock will stay put, without swinging!

Which of the following is stable system?

Which of the following systems is stable? Explanation: Stability implies that a bounded input should give a bounded output. In a,b,d there are regions of x, for which y reaches infinity/negative infinity. Thus the sin function always stays between -1 and 1, and is hence stable.

Which controller is used to increase the stability of the system?

The proportional derivative controller is used to improve the stability of control system without affecting the steady state error.

How do you make an unstable system stable?

Which of the following should be done to make an unstable system stable ?

1. A. The gain of the system should be decreased.
2. The gain of the system should be increased.
3. The number of poles to the loop transfer function should be increased.
4. The number of zeros to the loop transfer function should be increased.

What is conditionally stable system?

Conditionally stable systems are stable only when the loop gain is within a certain range. This stable range can be violated not only during large signal transient response, but during power up, low line, and other temporary conditions.

How do you know if a transfer function is stable?

Transfer function stability is solely determined by its denominator. The roots of a denominator are called poles. Poles located in the left half-plane are stable while poles located in the right half-plane are not stable.

Do zeros affect stability?

As s approaches a zero, the numerator of the transfer function (and therefore the transfer function itself) approaches the value 0. Addition of zeros to the transfer function has the effect of pulling the root locus to the left, making the system more stable.

What makes a transfer function unstable?

When the poles of the closed-loop transfer function of a given system are located in the right-half of the S-plane (RHP), the system becomes unstable. When the poles of the system are located in the left-half plane (LHP) and the system is not improper, the system is shown to be stable.

What is an unstable system?

A system itself is said to be unstable if at least one of its state variables is unstable. In continuous time control theory, a system is unstable if any of the roots of its characteristic equation has real part greater than zero (or if zero is a repeated root).

What is the point of instability?

The stored elastic strain energy at the point of instability is σY2/2E per unit volume, and this is released when instability/’failure’ occurs, imparting kinetic energy to the broken halves. The effect is more pronounced for long wires and cables because the stored elastic energy at the point of instability is greater.

What happens when a physical system becomes unstable?

If the physical system becomes unstable, then it would destroy itself. – for a marginally stable system, the response remains constant and is oscillatory in nature. A marginally stable system is one which is stable for some bounded inputs, but unstable for other bounded inputs.

Is Sine Bibo stable?

In the given expression, we know that sine functions have a definite boundary of values, which lies between -1 to +1. So, whatever values we will substitute at xt, we will get the values within our boundary. Therefore, the system is stable.

Which of the following is a bounded signal?

Examples of bounded signals are sin(t), cos(t), u(t). All these three signals are bounded by an amplitude of value 1. ( The maximum possible value is 1). Consider a continuous-time signal x(t) such that x(t) has infinite-amplitude (value) at t= infinite as shown in figure 2 is an example of the unbounded signal.

How do you describe a stable system informally?

How do you describe a stable system informally? Explanation: When small inputs lead to output responses that do not tend to infinity. The output of such systems does not diverge if the input does not diverge.