Tính dãy quy luật sau:
$A=D^T[\frac{1}{n}]+D^T[\frac{1}{n-1}]+D^T[\frac{1}{n-2}]+...+D^T[\frac{1}{3}]+D^T[\frac{1}{2}]+D^{-1}[1]+D^{-1}[2]+D^{-1}[3]+...+D^{-1}[n-2]+D^{-1}[n-1]+D^{-1}[n]$
$B=D^T[\frac{1}{3n}]+D^T[\frac{1}{3n-2}]+D^T[\frac{1}{3n-4}]+...+D^T[\frac{1}{6}]+D^T[\frac{1}{4}]+D^T[\frac{1}{2}]+0+D^{-1}[2]+D^{-1}[4]+D^{-1}[6]+...+D^{-1}[3n-4]+D^{-1}[3n-2]+D^{-1}[3n]$
Vậy khi đó $A^2B+(A-1)B^2+(A+1).(B+3)=?$
Loga
Sinh Học lớp 12
