向量 $\boldsymbol{b}=\left[\begin{array}{l}3 \\ 1 \\ 4\end{array}\right]$ 在基 $\boldsymbol{a}_1=\left[\begin{array}{l}1 \\ 0 \\ 2\end{array}\right], \boldsymbol{a}_2=\left[\begin{array}{l}2 \\ 1 \\ 4\end{array}\right], \boldsymbol{a}_3=\left[\begin{array}{l}3 \\ 1 \\ 5\end{array}\right]$ 下的坐标向量为