无穷级数,高等数学,求详细步骤,谢谢。

2025-05-01 02:58:11
推荐回答(2个)
回答1:

九. ρ= lim[2(n+1)+1]/(2n+1) = 1
x = ±1 时级数发散, 故收敛域 x ∈(-1, 1).
S(x)= ∑(2n+1)x^n
= 2∑(n+1)x^n - ∑x^n
= 2S1(x) - x/(1-x) x ∈(-1, 1).
∫<0,x>S1(t)dt = ∑∫<0,x>(n+1)t^ndt
= ∑x^(n+1) = x^2/(1-x) , x ∈(-1, 1).
S(x) = 2[x^2/(1-x)]' - x/(1-x)
= (2x-x^2)/(1-x)^2- x/(1-x) = x/(1-x)^2 x ∈(-1, 1).

回答2:

我大一,好像不会