Exercise 3.4.1: Verify the following identities involving regular expressions. * a) R+S=S+R. b) (R+S) +T = R + (S+T). c) (RS)T = R(ST). d) R(S+T) = RS + RT. e) (R+S)T = RT + ST. * f) (R')' = R'. g) ( + R)' = R'. h) (R'S') = (R+S)