Finding the angular spread of a diffraction minima?

[Peter Andrews]

1. Homework Statement
Light of wavelength 6000Å illuminates a single slit of width 10^-4m. Calculate the angular spread of first diffraction minima.

Homework Equations

d*y/D = nλ
Y = nλ/a for minima
Y = (2n±1)λ/a for maxima
Y stands for the position on screen, d is slit width and D is separation between screen and slit.

The Attempt at a Solution

I understand that the angular spread of any maxima is the difference in the angles subtended by the two minima on either side of it. But what about angular spread of a minima? Is it the difference in the angles subtended by the two maxima on its either side?

 

[Charles Link]

Normally the width of the diffraction minima is a problem that is not addressed because there doesn't seem to be a precise answer to the question. Perhaps your instructor can provide further clarification.