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Putnam 2011 B3

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December 5, 2011
Putnamfunctionlimitcollege contests

Problem Statement

Let ff and gg be (real-valued) functions defined on an open interval containing 0,0, with gg nonzero and continuous at 0.0. If fgfg and f/gf/g are differentiable at 0,0, must ff be differentiable at 0?0?
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