Question

Which of the following statements is true?

(a) The polynomials are unstable at interval [-1, 1]

(b) The polynomials are marginally stable at interval [-1, 1]

(c) The polynomial doesn’t oscillate at interval [-1, 1]

(d) The polynomials crosses the axis m-1 times at [-1, 1]

I got this question during an internship interview.

Query is from Adaptive Array topic in division Phased, Adaptive and Binomial Arrays of Antennas

Answer 1

Correct choice is (b) The polynomials are marginally stable at interval [-1, 1]

Easiest explanation: The polynomials oscillate between -1 and 1 interval. So they are either stable or marginally stable. The polynomial crosses the axis m times in the interval [-1, 1].