# Homework Help: Equation derivation problem

1. Sep 10, 2010

### Daniiel

Hey
this is a pretty straight forward equation derivation, but when i do it and compare it to the solutions, mine is different to theirs.
The equation is
[PLAIN]http://img213.imageshack.us/img213/9790/ddaaad.jpg [Broken] where n1=1
for a concave lens (fish in a fish bowl) so r is negative

solving for i

they get, r/(n2+1)

and i get n2r/(n2+1)

there answer seems right for the question, but im just not sure how they canceled the n2

Last edited by a moderator: May 4, 2017
2. Sep 10, 2010

### rl.bhat

Post the actual problem in the book.

3. Sep 10, 2010

### Daniiel

[PLAIN]http://img228.imageshack.us/img228/593/dsdsdsaas.jpg [Broken]

p = r/2 n2 = water

Last edited by a moderator: May 4, 2017
4. Sep 10, 2010

### rl.bhat

The fish is inside the bowl. So the formula becomes

n1/p + n2/i = (n1 - n2)/r

Here n1 = 1.33 and n2 = 1.

Now simplify and find i.

5. Sep 10, 2010

### Daniiel

oh right
thanks alot

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook