MathDB
Putnam 1999 B1

Source:

December 22, 2012
Putnamlimittrigonometrycollege contests

Problem Statement

Right triangle ABCABC has right angle at CC and BAC=θ\angle BAC=\theta; the point DD is chosen on ABAB so that AC=AD=1|AC|=|AD|=1; the point EE is chosen on BCBC so that CDE=θ\angle CDE=\theta. The perpendicular to BCBC at EE meets ABAB at FF. Evaluate limθ0EF\lim_{\theta\to 0}|EF|.