Question

急！数学~an+1=an+1/(2n-1)*(2n+1),a1=1,求an

Answer 1

由题知an+1-an=1/2[1/2n-1-1/2n+1]
a2-a1=1/2[1-1/3]
a3-a2=1/2[1/3-1/5]
.
.
an-an-1=1/2[1/2n-3-1/2n-1]
把启手所有式子加起来等于罩纯an-a1=1/2[1-1/2n-1]=n-1/2n-1
故an=a1+n-1/2n-1=3n-2/悄闷嫌2n-1

Answer 2

1 - 2·[(4^n-1)/(4-1)-1] = [(6n-5)·4^n 5]/庆郑老3 所以誉升：T(n)=[(6n-5)·4^n 5]/9 an=2（丛绝2n-1），a1=b1=2，b

Answer 3

已乱尘经上传尺唤完毕，哗困禅正在审核，稍等