成等比数列因为a+c=2b,c^2=bd,1/c+1/e=2/d将第三式化简(e+c)/(ec)=2/d由第一式2=(a+c)/b代入上式有,(e+c)/(ec)=(a+c)/bd=(a+c)/(c^2)化简有,(e+c)/(e)=(a+c)/(c)即1+c/e=1+a/c即c/e=a/c故ae=c^2所以a,c,e成等比数列...