Answer the following with reference to the degree of a polynomial function.
(i) Define the degree of a polynomial function.
(ii) For each of the following functions, state its degree and classify it as Constant, Linear, Quadratic, Cubic or Higher:
(a) f1(x)=7
(b) f2(x)=3−2x
(c) f3(x)=4x2−5x+1
(d) f4(x)=−x3+6x
(e) f5(x)=2x4−x2+9
(iii) Arrange the five functions in ascending order of their degrees.