30．（2022•宝山区校级二模）已知单位向量a→\overrightarrow{a}a，b→\overrightarrow{b}b的夹角为θ\thetaθ，若θ∈[π3,π2]\theta \in [{\frac{\pi }{3},\frac{\pi }{2}}]θ∈[3π,2π]，则∣a→+b→∣\vert {\overrightarrow{a}+\overrightarrow{b}}\vert∣a+b∣的取值范围是 ___[2,3][\sqrt{2},\sqrt{3}][2,3]___．