acosx+bcos2x>=-1
acos(x+π)+bcos(2x+2π)>=-1
-acosx+bcos2x>=-1
2bcos2x>=-2
b>=1或b=-1
asinx-bcos2x>=-1
a(sinx+cosx)>-2
a√2(sinx+π/4)>-2
a>=√2
a+b最大=√2+1
acosx+bcos2x>=-1
acos(x+π)+bcos(2x+2π)>=-1
-acosx+bcos2x>=-1
2bcos2x>=-2
b>=1或b=-1
asinx-bcos2x>=-1
a(sinx+cosx)>-2
a√2(sinx+π/4)>-2
a>=√2
a+b最大=√2+1