If a function f defined by $$f(x) = \left\{ {\matrix{ {{{k\cos x} \over {\pi - 2x}}} & , & {if\,x \ne {\pi \over 2}} \cr 3 & , & {if\,x = {\pi \over 2}} \cr } } \right.$$ is continuous at $$x = {\pi \over 2}$$, then the value of k is

For the matrix $$X = \left[ {\matrix{ 0 & 1 & 1 \cr 1 & 0 & 1 \cr 1 & 1 & 0 \cr } } \right]$$, (X² $$-$$ X) is

Let X = {x² : x $$\in$$ N} and the function f : N $$\to$$ X is defined by f(x) = x², x $$\in$$ N. Then this function is

The corner points of the feasible region for a Linear Programming problem are P(0, 5), Q(1, 5), R(4, 2) and S(12, 0). The minimum value of the objective function Z = 2x + 5y is at the point