Compulsory education curriculum standard experimental teaching material, ninth grade, volume 2, mathematics, page 30, detailed explanation of the answers to group C questions, extra points.
Solution (1):∫EP//ab, ∴ EP/AB = PC/BC = (BC-X)/BC = (2-X)/2; EP =(2-x)/2ab ∵pf//ac∴pf/ac=bp/bc=x/2； PF = X/2。 And because1/2 * AC * ab * Sina = SABC =1∴ spef = x/2 * (2-x)/2 =1/4x? 0? 5- 1/2X