y=cos(x π/6)^2 cos(x π/6) =(cos(x π/6) 1/2)^2-1/4 因为x∈{-π÷3,2π÷3},所以cos(x π/6)∈(1/2,1) 所以当cos(x π/6)=1/2时,最小值为3/4 当cos(x π/6)=1时,最大值为2
记得采纳啊
y=cos(x π/6)^2 cos(x π/6) =(cos(x π/6) 1/2)^2-1/4 因为x∈{-π÷3,2π÷3},所以cos(x π/6)∈(1/2,1) 所以当cos(x π/6)=1/2时,最小值为3/4 当cos(x π/6)=1时,最大值为2
记得采纳啊