已知A1A2A3A4A5A6A7是圆内接正七边形,求证:1/边A1A2=1/边A1A3+1/边A1A4
已知A1A2A3A4A5A6A7是圆内接正七边形,求证:1/边A1A2=1/边A1A3+1/边A1A4
已知A1A2A3A4A5A6A7是圆内接正七边形,求证:1/A1A2=1/A1A3+1/A1A4
已知A1A2A3A4A5A6A7是圆内接正七边形,求证;1/A1A2=1/A1A3+1/A1A4
设A1A2A3A4A5A6A7是圆内接正七边形,求证:1/A1A2=1/A1A3+1/A1A4 .
圆内接正七边形A1A2A3A4A5A6A7,证明:1/A1A2=1/A1A3+1/A1A4
设A1A2A3.A7是圆内接正七边形,求证:1/(A1A2)等于1/(A1A3)+1/(A1A4)
数学归纳法证明(a1+a2+.+an)^2=a1^2+a2^2+.+an^2+2(a1a2+a1a3+.+a(n-1)*
设a1,a2,a3都不为0,若1/a1a2+1/a2a3=2/a1a3,证明a1,a2,a3成等差数列
已知数列{an},若1/a1a2+1/a2a3+…+1/anan-1=n/anan+1,求证{an}为等差数列.
已知n个正数满足a1a2...an=1,求证(2+a1)(2+a2)...(2+an)≥3^n
已知数列{1/an}为等差数列,且a1a3+a3a5+a5a1=3/5,a1a3a5=1/15,求a3
【急】已知数列an满足1/a1a2+1/a2a3+……1/an-1an=(n-1)/a1an,求证为等差数列