If $$\overrightarrow a $$ and $$\overrightarrow b $$ are two arbitrary vectors with magnitudes $$a$$ and $$b$$ respectively, $${\left| {\overrightarrow a \times \overrightarrow b } \right|^2}$$ will be equal to

What should be the value of $$\lambda $$ such that the function defined below is continuous at $$x = {\pi \over 2}$$?
$$f\left( x \right) = \left\{ {\matrix{ {{{\lambda \,\cos x} \over {{\pi \over 2} - x}},} & {if\,\,x \ne {\pi \over 2}} \cr {1\,\,\,\,\,\,\,\,\,\,,} & {if\,\,x = {\pi \over 2}} \cr } } \right.$$

What is the value of the definite integral? $$\,\,\int\limits_0^a {{{\sqrt x } \over {\sqrt x + \sqrt {a - x} }}dx\,\,} $$?

For a body completely submerged in a fluid, the centre of gravity (G) and centre of Buoyancy (O) are known. The body is considered to be in stable equilibrium is