A square of side "a" lies above the x-axis and has one vertex at the origin. The side passing through the origin makes an angle `alpha " where " oltalphaltpi/4` with the positive direction of x-axis, the equation of its diagonal not passing through the origin is

Options

A. `y(cos alpha-sin alpha)-x(sin alpha-cos 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

B