A square of side a lies above the x-axis and has one vertex at the origin. The side passing throuhg the origin makes an angle `alpha (0 lt alpha lt (pi)/(4))` with the positive direction of x-axis. Then the equation of its diagonal not passing through the origin is-

Options

A. `y (cos alpha + sin alpha) +x (cos alpha - sin alpha) = a`
B. `y(cos alpha - sin alpha ) -x (sin alpha - cos alpha)=a`
C. `y (cos alpha + sin alpha) + x( sin alpha - cos alpha) =a`
D. `y(cos alpha + sin alpha ) +x (sin alpha + cos alpha )=a`

Answer

A