摘 要: | 1 A . 2 D . 3 B . 4 C . 5 A . 6 C . 7 B . 8 B . 9 -2a. 1 0 1 80° -32 α . 1 1 甲∶乙 =2 ∶ 1 . 1 2 3 5 2 0 . 1 3 (1 )略 . (2 )证Rt△AED ∽Rt△DFB ,∴ AEDF =DEBF,即DE· DF =AE·BF .又 ∵CD =2DE= 2DF ,∴CD2 =2DE· 2DF =2DE·DF =2AE·BF .1 4 由前一方程得x2 -2 0 0 2 2 -12 0 0 2 2 x -12 0 0 2 2 =0 ,∴x2 -1 -12 0 0 2 2 x-12 0 0 2 2 =0 .设方程两根为x1,x2 ,且 x1>x2 ,则 x1+x2 =1 -12 0 0 2 2 ,x1·x2 =-12 0 0 2 2 .则 x1=1 ,x2 =-12 0 0 2 2 .同理 ,后一方程为…
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