15/10/28 12:52:45.14
a[1]=1
b[1]=2
a[n+1]=b[n]+d
b[n+1]=r a[n]
a[n+2]=r a[n] +d
a[n+2]-k =r {a[n]-k}
k =d/(1-r)
a[2m]=r^(m-1)(2+d-k) +k
a[2m-1]=r^(m-1)(1-k)+k
a[2m+1]=(r^m)(1-k)+k
b[2m]/a[2m]=r a[2m-1]/a[2m] → r (1-k)/(2+d-k)
b[2m+1]/a[2m+1]=r a[2m]/a[2m+1] → (2+d-k)/(1-k)
r(1-k)/(2+d-k)=(2+d-k)/(1-k)
r(1-k)^2=(2+d-k)^2
r(1-k)^2 =(2-kr)^2
r(1-2k+k^2)=4-4kr+(kr)^2
d=k(1-r)=-1 ±(|r-2|/√r)