∴∠CAE=∠BAD (the nature of the equation);

AC = ABAE=AD again. (known)

∴⊿cae≌⊿bad(sas),ce=bd； ∠AEC=∠ADB。

So: ∠ DEC+∠ EDA+∠ ADB = ∠ DEC+∠ EDA+∠ AEC = 90? .

Therefore: ∠DCE=90? , CE vertical BD

(2) solution: CE = BDCE vertical BD. (Certified)

∴s⊿dbe=ce*bd/2=6*6/2= 18(cm？ ).

The conclusion is wrong, it should be S⊿DCA=S⊿ABE.

It is proved that the expansion project of CN⊥AD in N,BM⊥EA will be carried out until 2000.

∵∠NAM=∠CAB=90？ .

∴∠nac=∠mab；

AC = AB∠ANC=∠AMB=90 again? .

∴⊿ANC≌⊿AMB(AAS),CN=BM.

And AD=AE, then: AD*CN/2=AE*BM/2.

Namely: S⊿DCA=S⊿ABE.