当0
问题描述：
当0
答
[1/x^2+1/(a-x)^2]•a^2=[1/x^2+1/(a-x)^2]•[x+(a-x)]^2=[1/x^2+1/(a-x)^2]•[x^2+2x(a-x)+(a-x)^2]=1+2x(a-x)/x^2+(a-x)^2/x^2+ x^2/(a-x)^2+2x(a-x) /(a-x)^2+1=1+2(a-x)/x+(a-x)^2/x^2+ x^2/(a-x...