f（x）=2cos²x+√3*sin2x+m
=1+cos2x+√3sin2x+m
=2sin(2x+π/6)+m+1
(1) T=2π/2=π
2kπ-π/2≤2x+π/6≤2kπ+π/2
2kπ-2π/3≤2x≤2kπ+π/3
kπ-π/3≤x≤kπ+π/6
注意到 [0,π]
增区间[0,π/6] 和[2π/3,π]
(2) x∈[0,π/6]
2x+π/6∈[π/6,π/2]
sin(2x+π/6)∈[1/2,1]
f(x)∈[2+m,m+3]
2+m>-4且m+3