已知函數f(x)=ax-b/x-2lnx,f(1)=0 (1)若函數影像在x=1處的切線斜率是0,且A(n+1)=f`{1/[A(n)-n+1]}-n^2+1,已知A(1)=4,求證:A(n)不小於2n+2 (2)在(1)的條件下,比較Sum(從1到n)1/[1+A(i)]與0.4大小關係

已知函數f(x)=ax-b/x-2lnx,f(1)=0 (1)若函數影像在x=1處的切線斜率是0,且A(n+1)=f`{1/[A(n)-n+1]}-n^2+1,已知A(1)=4,求證:A(n)不小於2n+2 (2)在(1)的條件下,比較Sum(從1到n)1/[1+A(i)]與0.4大小關係

f(1)=0 => a-b=0 =>a=b(1)f'(x)=a+b/x^2-2/x f'(1)=k=0 =>a+b-2=0 =>a=b=1=>f(x)=1-1/x-2lnx f'(x)=1+1/x^2-2/x=(1-1/x)^2A(n+1)=f'(1/(A(n)-n+1))-n^2+1=(A(n)-n)^2-n^2+1=A(n)^2-2nA(n)+1用數學歸納法證明A(n)>=…