Remember ∠OBE=x, then do = ob * tan ∠ DBO = ∠ 2/2 * AB * Tan (45 degrees-x) = ∠ 2/2 * ab * (1-tanx)/(/kloc- AD = AO-DO =√2/2 * AB( 1-( 1-tanx)/( 1+tanx))=√2/2 * AB * 2 tanx/( 1+tanx)，OE=OB*tan∠OBE=√2/2*AB*tanx，EC=OC-OE=√2/2*AB( 1-tanx)
Calculate DOX OE =1/2 * AB 2 * TANX * (1-TANX)/(1+TANX), ADXEC =1/2 * AB 2 * 2 TANX * (1).
(2) the same as (1), first calculate BO=AB*cos(a/2), AO=OC=AB*sin(a/2), write ∠OBE=x, then do = ob * tan ∠ dbo = ab * cos (a In the same way, we can get the values of AD, OE and CE (write the answer orz directly), and finally calculate DOX OE = AB 2 * COS 2 (a/2) * tanx * (1-tanx)/(1+tanx). adxce = ab 2 *(sin 2(a/2)+cos 2(a/2)* tanx *( 1-tanx)/( 1+tanx))-sin(a/2)* cos(a/2)。 AD×EC does not hold water.