If $\overrightarrow{\mathbf{a}} = (1, - 1)$ and $\overrightarrow{\mathbf{b}} = ( - 2,m)$ are two collinear vectors, then $m$ is equal to

Question

Dr. Abubacker · Accepted Answer

(a)
Since, $\overrightarrow{\mathbf{a}}$ and $\overrightarrow{\mathbf{b}}$ are collinear vectors.
$	herefore\ \overrightarrow{\mathbf{a}} = \lambda\overrightarrow{\mathbf{b}}$
$\Longrightarrow \ \widehat{\dot{\mathbf{i}}} - \widehat{\dot{\mathbf{j}}} = \lambda\left( - 2\widehat{\dot{\mathbf{i}}} + m\widehat{\dot{\mathbf{j}}} ight)$
$\Longrightarrow 1 = - 2\lambda,\  - 1 = \lambda m$
$\Longrightarrow \ \lambda = - \frac{1}{2},\ m = - \frac{1}{\lambda}$
$\Longrightarrow m = 2$

Q. If $\overrightarrow{\mathbf{a}} = (1, - 1)$ and $\overrightarrow{\mathbf{b}} = ( - 2,m)$ are two collinear vectors, then $m$ is equal to

Explanation

Reviewed by Dr. Abubacker

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