For a scalar function $$f(x,y,z)=$$ $${x^2} + 3{y^2} + 2{z^2},\,\,$$ the gradient at the point $$P(1,2,-1)$$ is

A square matrix $$B$$ is symmetric if ____

In the solution of the following set of linear equations by Gauss-elimination using partial pivoting $$$5x+y+2z=34,$$$ $$$4y-3z=12$$$ and $$$10x-2y+z=-4.$$$
The pivots for elimination of $$x$$ and $$y$$ are

In quadrantal bearing system, bearing of a line varies from