设公比为q
因Am=a1*q^(m-1)=x (1)
An=a1*q^(n-1)=y (2)
(2)/(1) q^(n-m)=y/x q=(y/x)^[1/(n-m)]
A(n+m)=a1*q^(m+n-1)
=[a1*q^(m-1)]*q^n
=x*(y/x)^[n/(n-m)]
=x^[m/(m-n)]*y^[n/(n-m)]
希望能帮到你O(∩_∩)O
A1=a,等比=q,
Am=x; An=y,
A(m+n) =a*q^(m+n-1) = q*x*y/a;
Am * An= a*a*q^(m+n-2)