Question

Viết vectơ \(\overrightarrow{u}\) dưới dạng \(\overrightarrow{u}=x\overrightarrow{i}+y\overrightarrow{j}\) khi biết tọa độ của \(\overrightarrow{u}\) là :

\(\left(2;-3\right);\left(-1;4\right);\left(2;0\right);\left(0;-1\right);\left(0;0\right)\)

Answer 1

\(\overrightarrow{u}\left(2;3\right)=2\left(1;0\right)+3\left(0;1\right)=2\overrightarrow{i}+3\overrightarrow{j}\).
\(\overrightarrow{u}\left(-1;4\right)=-\left(1;0\right)+4\left(0;1\right)=-\overrightarrow{i}+4\overrightarrow{j}\).
\(\overrightarrow{u}\left(2;0\right)=2.\left(1;0\right)+0.\left(0;1\right)=2\overrightarrow{i}+0\overrightarrow{j}\).
\(\overrightarrow{u}\left(0;-1\right)=0.\left(1;0\right)-1.\left(0;1\right)=0\overrightarrow{i}-\overrightarrow{j}\).
\(\overrightarrow{u}\left(0;0\right)=0.\left(1;0\right)+0.\left(0;1\right)=0\overrightarrow{i}+0\overrightarrow{j}.\)