f(x)=cos(x+2/3π)+2cos²x/2,求值域,单调增区间.

问题描述:

f(x)=cos(x+2/3π)+2cos²x/2,求值域,单调增区间.

若题目是f(x)=cos(x+2/3 π)+2 cos²x/2则解为:f(x)=-1/2cosx-2分之根号3sinx+1+cosx =1/2cosx — 2分之根号3sinx =sin(x+ π/6)+1因为sin(x+ π/6)∈【-1,1】所以f(x)的值域为...