When simplified, the sum `1/2+1/6+1/(12)+1/(20)+1/(30)+\ ddot+1/(n(n+1))` is equal to `1/n` (b) `1/(n+1)` (c) `n/(n+1)` (d) `(2(n-1))/n`

When simplified,the sum (1)/(2)+(1)/(6)+(1)/(12)+(1)/(20)+(1)/(30)+backslash+(1)/(n(n+1)) is equal to (1)/(n)(b)(1)/(n+1)(c)(n)/(n+1) (d) (2(n-1))/(n)

sum_(n=1)^(99) n! (n^2 + n+1) is equal to :

The sum of the series 2/3+8/9+(26)/(27)+(80)/(81)+ to n terms is (a) n-1/2(3^(-n)-1) (b) n-1/2(1-3^(-n)) (c) n+1/2(3^n-1) (d) n-1/2(3^n-1)

The value of sum_(r=1)^(n)(-1)^(r+1)(^nCr)/(r+1) is equal to a.-(1)/(n+1) b.(1)/(n) c.(1)/(n+1) d.(n)/(n+1)

If N=1/2+1/6+1/12+1/20+1/30+………+1/156 what is the value of N?

Simplify. 1 / (n!) - 1 / ((n - 1)!) - 1 / ((n -2)!)

The sum sum_(n=1)^(10) ( n(2n-1)(2n+1))/( 5) is equal to _______.

The value of sum_(r=1)^n(-1)^(r+1)("^n C r)/(r+1) is equal to a. -1/(n+1) b. 1/n c. 1/(n+1) d. n/(n+1)

The sum of the series 1/(1!(n-1)!)+1/(3!(n-3)!)+1/(5!(n-5)!)+…..+1/((n-1)!1!) is = (A) 1/(n!2^n) (B) 2^n/n! (C) 2^(n-1)/n! (D) 1/(n!2^(n-1)