The value of `cot(sum_(n=1)^2 cot^-1(1+sum_(k=1)^n 2k))` is (a) `23/25` (b) `25/23` (c) `23/24` (d) `25/26`

The value of cot (sum_(n=1)^(23) cot^(-1) (1 + sum_(k=1)^(n) 2k)) is

The value of sum_(r=1)^(n+1)(sum_(k=1)^(n)C(k,r-1))=

The value of cot sum_(n=1)^(oo)cot^(-1)((2)/(n^(2))sum_(n=1)^(n)k^(3))

The value of cot sum_(n=1)^(19)(cot^(-1)(1+sum_(p=1)^(n)2p)) is equal to ( a )(21)/(19) (b) (19)/(21)(c)-(19)/(21) (d) -(21)/(19)

The value of 23C_(6)+sum_(j=1)^(5)28-jC_(5)+sum_(k=1)^(5)33-kC_(28-k) is

The value of lim_(ntooo)sum_(r=1)^(n)cot^(-1)((r^(3)-r+1/r)/2) is

Evaluate : sum_(k=1)^n (2^k+3^(k-1))