掩面佛牌可怕的一面:高二数学 急
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0<x<(1/a)<(1/2) 求证 x-x^2<1/(1+a)
x-x^2<1/(1+a)
=> x(1-x)<1/(1+a)
yin wei :0<x<(1/a)<(1/2)
suo yi : 2<a<(1/x) => a<1/x ,
0<x<1,
1/(1-x)>1,
you yuan shi de 1/[x(1-x)] > (1+a)
=> 1/x + 1/(1-x) > (1+a)
yin wei: 1/x > a , 1/(1-x) > 1
suo yi : 1/x + 1/(1-x) > 1+a
suo yi jie lun cheng li