Which of the following is NOT a comer point of the feasible region determined by the constraints:

$$ \begin{aligned} & x+2 y \leq 4 \\ & x+y \geq 2 \\ & x \geq 0 \text { and } y \geq 0 \end{aligned} $$

The angle between the two lines whose direction cosines satisfy the relations $\boldsymbol{l}+\boldsymbol{m}+\boldsymbol{n}=\mathbf{0}$ and $\boldsymbol{l}^{\mathbf{2}}=\boldsymbol{m}^{\mathbf{2}}+\boldsymbol{n}^{\mathbf{2}}$ is

In how many ways can the squares of a $\mathbf{4} \times \mathbf{2}$ grid ( 4 rows and 2 columns) be filled with the letters of the word 'SPHERE' such that each row contains at least one letter?

The value of the expression $\cos ^{-1}\left(\cos \frac{7 \pi}{6}\right)+\sin ^{-1}\left(\sin \frac{22 \pi}{3}\right)+\tan ^{-1}\left(\tan \frac{4 \pi}{5}\right)$ is: