y已知F(X)=3X^2-2X,数列AN的前N项和为SN,点(N,SN)均在函数y=f(x)y已知F(X)=3X^2-2X,数列AN的前N项和为SN,点(N,SN)均在函数y=f(x)上,求AN BN=1/AN*A(N+1)使BN前N项和Tn,求使得TN

问题描述:

y已知F(X)=3X^2-2X,数列AN的前N项和为SN,点(N,SN)均在函数y=f(x)
y已知F(X)=3X^2-2X,数列AN的前N项和为SN,点(N,SN)均在函数y=f(x)上,求AN BN=1/AN*A(N+1)使BN前N项和Tn,求使得TN

x=n f(x)=Sn代入函数方程:Sn=3n²-2nn=1时,S1=a1=3-2=1n≥2时,Sn=3n²-2n S(n-1)=3(n-1)²-2(n-1)an=Sn-S(n-1)=3n²-2n-3(n-1)²+2(n-1)=6n-5n=1时,a1=6-5=1,同样满足.数列{an}的通项公式为an=...