∴AF=3/2,FB= 1/2

Connect AE, angle AEB=90 degrees.

ef^2=af*fb=3/4==>； EF=√3/2

Tangent angle ebf = ef/FB = √ 3 = = > Angle EBF=60 degrees, BE= 1.

CDE angle = EBF angle =60 degrees

∫CE = 1 = = >BC= 1+ 1=2=AB

∴⊿ABC equilateral triangle

Angle CAB= angle CED=60 degrees

∴⊿DEC equilateral triangle == >CD= 1