\(CD = 2DE + AE\)
证明:如图,在\(CD\)上截取\(BG = BE\),

\(\because \angle BEC = 60^\circ \),
\(\therefore \Delta BGE\)是等边三角形,
\(\therefore \angle BGC = \angle AED = 120^\circ \),
\(\because \angle BCE = \angle DAE = \alpha \),
\(\therefore \Delta BCG \cong \Delta DAE(AAS)\),
\(\therefore AE = CG\),
\(\because EG = BE = DE\),
\(\therefore CD = 2DE + CG\),
即\(CD = 2DE + AE\).