Geomertical optics- derivation of graph of (u+v) against u

may i know how to derive the the sha[pe of graph and get the point of min (2f , 4f) ? i really have no idea how to get the shape of the graph and the min point.

may i know how to derive the the sha[pe of graph and get the point of min (2f , 4f) ? i really have no idea how to get the shape of the graph and the min point.

Ling,

Can you please scan a larger area of the question?

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Örsan Yüksek

Last edited by orsanyuksek; Sep 25th 2014 at 12:29 AM.