30°
向量a·向量b=|a||b|cos60°=1,
=> 向量a·向量a+2b=|a|²+2向量a·向量b=6,
|a+2b|=2√3,
设夹角为α,
则cosα=(向量a·向量a+2b)/(|a||a+2b|)=6/(2×2√3)=√3/2,
则α=30°