Which is the constructive interference formula for diffraction grating problems?

dsin =

dcos =

dcos = n

dsin = n

The formula applied in diffraction gratings is:

dsin (θ) = nλ

where d is the distance between two adjacent openings in the grating, θ is the angle between two minima or maxima of light, n is the order of the maxima or minima formed and λ is the wavelength of the light being diffracted.