Let f:R→R be defined by f(x)=2x2−8x+5.
a. (a) Rewrite f(x) in the completed–square form and hence find the coordinates of its vertex.
b. (b) Determine the least interval containing x=3 on which f becomes one–one.
c. (c) For the interval obtained in part (b), find the explicit expression for f−1 and state its domain and range.