(1)max=3/2 (x=(2k+1)π,k=...,-2,-1,0,1,2.) min=1/2 (x=2kπ,k=...,-2,-1,0,1,2.) (2)max=3(x=7/12π+kπ,k=...,-2,-1,0,1,2.) min=-3(x=1/12π+kπ,k=...,-2,-1,0,1,2.)