1、f(-7π)=【sin(-7/6π)】+【cos(-7/6π)】=sin5/6π+cos5/6π=sin1/6π-cos1/6π=1/2-（根号3）/2
2、2x∈[0,π],2x∈[0,π/2]时,f(x)=sin2x+cos2x=(根号)2sin(2x+/4π),[-根号2,根号2]
2x∈[π/2,π]时,f(x)=sin2x-cos2x=(根号)2sin(2x-/4π),[-根号2,根号2]
f(x)取值范围为),[-根号2,根号2]
3、