CBSE [ All India ]_XII_Mathematics_2010_Set III

Write the principal value of sec^-1 (-2).

Write the distance of the following plane from the origin :

2x – y + 2z + 1 = 0

What positive value of x makes the following pair of determinants equal ?
 

Write the adjoint of the following matrix :

Write a vector of magnitude 9 units in the direction of vector