Consider a continuous-time system with input x(t) and output y(t) give...
given y(t) = x(t) cos(t)
It satisfies both additivity and Homogentity principles, so it is linear
If the input is delayed by t0
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Consider a continuous-time system with input x(t) and output y(t) give...
Linear and Time-Varying System
To determine the linearity and time-invariance of the given system, let's analyze its properties one by one.
Linearity:
A system is considered linear if it satisfies the properties of superposition and homogeneity.
Superposition:
In a linear system, if x1(t) produces y1(t) and x2(t) produces y2(t), then any linear combination of these inputs, ax1(t) + bx2(t), should produce a corresponding linear combination of the outputs, ay1(t) + by2(t).
Let's test this property for the given system:
y1(t) = x1(t) * cos(t)
y2(t) = x2(t) * cos(t)
Now, let's consider the linear combination of the inputs:
y(t) = a * (x1(t) * cos(t)) + b * (x2(t) * cos(t))
Expanding the equation:
y(t) = a * x1(t) * cos(t) + b * x2(t) * cos(t)
Comparing this with the output produced by the linear combination of individual inputs:
ay1(t) + by2(t) = a * (x1(t) * cos(t)) + b * (x2(t) * cos(t))
Since both equations are the same, the system satisfies the superposition property and is linear in nature.
Time-Varying:
A system is considered time-invariant if its behavior remains the same over time. In other words, a time shift in the input results in the same time shift in the output.
To check the time-invariance property, let's consider a time-shifted input:
y(t - t0) = x(t - t0) * cos(t - t0)
Comparing this with the original output equation:
y(t) = x(t) * cos(t)
We can see that the time shift in the input also affects the output. Therefore, the system does not exhibit time-invariance.
Conclusion:
Based on the analysis, the given system is linear due to satisfying the superposition property. However, it is time-varying because a time shift in the input results in a corresponding time shift in the output. Therefore, the correct answer is option 'C' - linear and time-varying.
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