I see. To make life easier, approximations are used. Thanks for your comment :)
Never considered an arc acting as a straight line.
And yea my a is s. Neat how you saw the triangle I used.Though to be truthful, I hate approximations. Sticks out like a sore thumb.
I guess I would need a really...
Hi hi, first post ^^
Anyway, I encountered this little problem with the derivation of Young's double slit formula. The standard derivation found on the internet and my textbook is shown here: http://schools.matter.org.uk/content/interference/formula.html
When deriving, a few errors had...