Find the local extrema of
f(x)=root(3)cosx + sinx, 0<=x<=2pi
1. why root(3) at x=2pi is local maximum
and root(3) at x=0 is local minimum ?
2. they are not absolute extrema, why they can be local extrema?
3. how to know whether root(3) at x=2pi is local maximum or local minimum ? Can't it be local minimum as the answers are both root(3) ?
please explain