设向量,若满足,则 .
设sin2α=-sinα,α∈,则tan2α=________.
已知α+β=,则cos2α+cos2β+cosαcosβ=________.
若≤α≤,则=________.
函数f(x)=sinxcosx的最小正周期是________.
若sin(+θ)=,则cos2θ=________.