4. This is an exercise about the geometry of signals, and a possible exam-type question. All signals here are over the interval 0 < t S 1. We want to obtain mutually perpendicular polynomial signals. We start with fo(t) 1 for all t. (a) Find the value of the constant a so that the signal fi (t)t+a is perpendicular to the signal fo perpendicular to both fo and fi is perpendicular to each of fo, fı, and f. (b) Find the values of constants bi and b so that the signf(t2 + bit + b2 is e values of constants b1 an 2 1S (c) Find the values of constants c, 2, and c so that the signal fa(t) +ct+tc C3 4. This is an exercise about the geometry of signals, and a possible exam-type question. All signals here are over the interval 0