Optics: Destructive Interference

[SHAWN JAMES]

Homework Statement:

I had a question on where i use (m+1/2), in the equation dsin(theta)=Lambda(m).

Relevant Equations:

dsin(theta)=lambda(m)

I thought if the question asks for the first minimum or the first dark fringe you use (m+1/2) but i am not getting the right answer. I was hoping if someone could tell me in what situations the (m+1/2) would apply? Thanks in advance.

 

[haruspex]

Homework Statement:: I had a question on where i use (m+1/2), in the equation dsin(theta)=Lambda(m).
Relevant Equations:: dsin(theta)=lambda(m)

for the first minimum or the first dark fringe you use (m+1/2)

Where m is what?
Please post the whole question and your attempt.