a^y = a^x [1 a^(y-x)] BE=BC CE=BC CA/2
问题描述：
a^y = a^x [1 a^(y-x)] BE=BC CE=BC CA/2
∴(√a √b) 2;≥0 ∴a b-2√ab≥0 abs(x) abs(y)
答
f(x)=loga(x^2-ax)在(-1/2,0)-1/2