Selections 2, 3, 5, 6 are polynomials.
1 and 4 are not. The coefficients don't have to be integers, but the powers of the variables need to be positive integers. In 1, you have x^-1. in 4, you have x^(1/2).
The correct answer is: [A]: " t = 15n " .
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Answer:
1. Discrete-time signals are represented mathematically as sequences of numbers. A sequence of numbers x, in which the nth number in the sequence is denoted x[n],
1 is
formally written as
x = {x[n]}, −∞ <n< ∞, (2.1)
2. where n is an integer. In a practical setting, such sequences can often arise from periodic
sampling of an analog (i.e., continuous-time) signal xa(t). In that case, the numeric value
of the nth number in the sequence is equal to the value of the analog signal, xa(t), at
time nT : i.e.,
x[n] = xa(nT ), −∞ <n< ∞. (2.2)
Step-by-step explanation:
