I was set a problem describing a series of 6 slits, spacing of 0.4mm and diffracting light of wavelength 600nm onto a screen 4m away. I had to graph the intensity across the screen. Now I managed that ok, but then it wants to now how the resulting graph would change if the slits had finite width 0.15nm. Now, the problem for me is that although I get the principle (that the pattern I have already will be mapped onto the overall diffraction pattern) I have no real idea how to go about combining the many many formulae that seem to be out there to find the actual pattern. Any help would be much appreciated.