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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 n_{1}=1

for a concave lens (fish in a fish bowl) so r is negative

solving for i

they get, r/(n_{2}+1)

and i get n_{2}r/(n_{2}+1)

there answer seems right for the question, but im just not sure how they canceled the n_{2}

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# Homework Help: Equation derivation problem

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