+dfrac (sin n)({2)^n} ;-|||-(2) _(n)=1+dfrac (1)({2)^2}+dfrac (1)({3)^2}+... +df
,dfrac (ntimes 100)(n)} B S=-|||- dfrac {1)(n),... ,dfrac (ntimes 100)(n)} C S=-
+(n)^3);-|||-(2) lim _(narrow infty )n[ dfrac (1)({(n+1))^2}+dfrac (1)({(n+2))^2
_(n)=((-1))^n+1dfrac (1)(sqrt {n)}-|||-C. _(n)=sin dfrac (npi )(2)-|||-D. _(n)=d
+dfrac (n)({n)^2+n+n})=dfrac (1)(2)证明:
+dfrac (1)(n(n+1)) =-|||-(3) lim _(narrow infty )(dfrac (1)(2)+dfrac (3)({2)^2}+
+dfrac (sin npi )(n+dfrac {1)(n)}]
lim _(narrow infty )(dfrac (1)({n)^2+n+1}+dfrac (2)({n)^2+n+2}+... +dfrac (n)({n
16.-|||-□A、 (int )_(0)^1xdx=lim _(narrow infty )sum _(n=1)^infty dfrac (i)(n)cdo
+(n-1)ln dfrac (n-1)(n)] = ____