求级数sum _(n=1)^infty dfrac (1)(n(n+1)(n+2))的和。

求级数 sum _(n=1)^infty dfrac (1)(n(n+1)(n+2)) 的和.-|||-__

求幂级数 sum _(n=1)^infty n(n+1)(x)^n 的收敛域及和函数并求 sum _(n=1)^infty dfrac (n(n+1))({2)

级数 sum _(n=1)^infty (sqrt (n+2)-2sqrt (n+1)+sqrt (n))= __ .

,求幂级数 sum _(n=1)^infty dfrac (2n-1)({2)^n}(x)^2n-2 的和函数,并求级数 sum _(n=1)^infty df

下列级数绝对收敛的是()A.sum _(n=1)^infty dfrac ({(-1))^n+1}(2n+1)B.sum _(n=1)^infty dfrac

+(n)^3);-|||-(2) lim _(narrow infty )n[ dfrac (1)({(n+1))^2}+dfrac (1)({(n+2))^2

幂级数sum _(n=1)^infty dfrac ({(-1))^n}(2n-1)(x)^2n-1(|x|lt 1)的和函数sum _(n=1)^infty

+dfrac (1)({2)^n})-|||-1/2^n);(12)-|||-(13) lim _(narrow infty )dfrac ((n+1)(n+2

1.求下列幂级数的收敛域(或收敛圆):-|||-(1) sum _(n=1)^infty dfrac (1)({2)^n}(x)^2n-1;-|||-(2) s

A12.1.4 下列级数中,收敛的级数是 __-|||-(A) sum _(n=1)^infty =dfrac (-2)(n) (B) sum _(n=1)^i