Mathematics Vectors & 3D Geometry questions from JEE Main 2018.
An angle between the lines whose direction cosines are given by the equations, $l+3 m+5 n=$ 0 and $5 l m-2 m n+6 n l=0$, is
If $\vec{a}, \vec{b}$, and $\overrightarrow{\mathrm{c}}$ are unit vectors such that $\vec{a}+2 \vec{b}+2 \overrightarrow{\mathbf{c}}=\overrightarrow{0}$, then $|\vec{a} \times \overrightarrow{\mathbf{c}}|$ is equal to
If $\vec{a},\vec{b},\vec{c}$ are unit vectors such that $\vec{a}+2\vec{b}+2\vec{c}=\vec{0}$, then $|\vec{a}\times \vec{c}|$ is equal to :