Find the sum of the series `sum_(r=1)^n rxxr !dot`

Find the sum of the series sum_(r=11)^(99)(1/(rsqrt(r+1)+(r+1)sqrtr))

Find the sum of series sum_(r=1)^(n)r.x^(r-1), using calculus.

Sum of the series sum_(r=1)^(n) (r^(2)+1)r! is

find the sum of the series sum_(r=0)^(n)(-1)^(r)*^(n)C_(r)[(1)/(2^(r))+(3^(r))/(2^(2r))+(7^(r))/(2^(3r))+(15^(r))/(2^(4r))... up to m terms ]

Sum of the series sum_(r=1)^(n)(r^(2)+1)r!, is

Find the sum of the series sum_(r=0)^(50)(""^(100-r)C_(25))/(100-r)

If the sum of the series sum_(n=0)^(oo)r^(n),|r|<1 is s then find the sum of the series sum_(n=0)^(oo)r^(2n)

The sum of the series sum_(r=1)^(n)(-1)^(r-1)*nC_(r)(a-r) is equal to :