The non-zero verctors $\vec{a}, \vec{b}$ and $\vec{c}$ are related by $\vec{a}=8 \vec{b}$ and $\vec{c}=-7…
The non-zero verctors $\vec{a}, \vec{b}$ and $\vec{c}$ are related by $\vec{a}=8 \vec{b}$ and $\vec{c}=-7 \vec{b}$. Then the angle between $\vec{a}$ and $\overrightarrow{\mathrm{c}}$ is
0
$\pi / 4$
$\pi / 2$
$\pi$
Solution
Since $\vec{a}=8 \vec{b}$
$
\overrightarrow{\mathrm{c}}=-7 \overrightarrow{\mathrm{b}}
$
$\therefore \vec{a}$ and $\vec{b}$ are like vectors and $\vec{b}$ and $\vec{c}$ are unlike.
$\Rightarrow \vec{a}$ and $\vec{c}$ will be unlike
Hence, angle between $\vec{a}$ and $\vec{c}=\pi$