Please help with all steps

Dear Student,

W h e n l i g h t f r o m t w o c o h e r e n t s o u r c e s i n t e r a c t a n d f o r m n t h m i n i m a t h a n p a t h d i f f e r e n c e = (2 n - 1) \frac{λ}{2} [H e r e n i s i n t e g e r] S o, S X - S' X = (2 \times 2 - 1) \frac{λ}{2} = \frac{3 λ}{2} 4.5 = \frac{3 λ}{2} λ = \frac{2 \times 4.5}{3} = 3 c m

Regards,