a=(1/2,2,sinx),集合b=(-根号3/2,cosx)若a∩b=(y),即sinx=-根号3/2x=2kπ＋4π/3 cosx=-1/2或x=2kπ＋5π/3cosx=1/2 舍去即x=2kπ＋4π/3,y=-根号3/22. sinx=cosxx=kπ＋π/4sinx=cosx=±√2/2即x=2kπ＋π/4y=√2/2...