假设AE/AB=x,则
由S△AEF=2S△EBC
有
x^2*S△ABC=2*(1-x)*S△ABC
x^2=2-2x
x^2+2x-2=0
x=-1+sqrt3
S△CEF=S△ABC-S△AEF-S△EBC=S△ABC-3S△EBC=1-3*(1-x)=3x-2=3sqrt3-5
假设AE/AB=x,则
由S△AEF=2S△EBC
有
x^2*S△ABC=2*(1-x)*S△ABC
x^2=2-2x
x^2+2x-2=0
x=-1+sqrt3
S△CEF=S△ABC-S△AEF-S△EBC=S△ABC-3S△EBC=1-3*(1-x)=3x-2=3sqrt3-5