oh I see now thank you!
I think my method would have only worked if the question was asking for the second bright fringe, as the distance from the central maximum to the first dark band would not be delta X but would be 1/2ΔX
I thought it wasn't necessary as it was more an issue with the concept as I was able to reach the correct answer on my own using the Xn formula, so sorry!
Updated
Homework Statement
A light source shines light of wavelength 490nm onto a pair of slits separated by 0.44m. Calculate the angular location and the location in cm of the second order dark fringes on a screen 1.4m from the slit
Homework Equations
Xn = (n-1/2)L lambda/d
delta x = L lambda/d
The...