Question

已知向量OA=（2asin²x,a）,向量OB=（-1,2√3sinxcosx+1）,0为坐标原点,a≠0

Answer 1

1

f(x)=-2asin²x+2√3asinxcosx+a+b

=(1-2sin²x)a+√3asin2x+b

=acos2x+√3asin2x+b

=2asin(2x+π/6)+b

g(x)=sinx单增区间[2kπ-π/2,2kπ+π/2]

2kπ-π/2≤2x+π/6≤2kπ+π/2

kπ-π/3≤x≤kπ+π/6

2

π/2