Sum of series : 1+2+3+......... +n is
(A)`((n)(n+1))/2` (B) n(n+1) (C) `((n+1)(n+2))/2` (D) none of these.

The arithmetic mean of 1,2,3,...n is (a) (n+1)/(2) (b) (n-1)/(2) (c) (n)/(2)(d)(n)/(2)+1

Sum of the series a^n+a^(n-1)b+^(n-2)b^2+………..+ab^n can be obtained by taking outt a^n or b^n comon and using the forumula of sum of (n+1) terms of G.P. N the basis of above information answer the following question:Coefficientoif xp, (0leplen) in 3^(n-1)+3^(n-2)(x+3)+3^(n-3)(x+3)^2+............+(x+30)^(n-1) is (A) ^nC_p3^n-p) (B) ^(n+1)C_p3^(n-p+1) (C) ^nC_p3^(n-p-1) (D) none of these

If A=[(2,-4),(1,-1)] the value of A^n is (A) [(3^n,(-4)^n),(1,(-1)^n)] (B) [(3n,-4n),(n,n)] (C) [(2+n,5-n),(n,-n)] (D) none of these

Find the sum of n terms of the series (1)/(2*4)+(1)/(4*6)+... (A) (n)/(n+1) (B) (n)/(4(n+1)) (C) (1)/((2n)(2n+2))( D) )(1)/(2^(n)(2^(n)+2))

The arithmetic mean of the series 1,2,4,8,16,....2^(n) is (2^(n)-1)/(n+1) (b) (2^(n)+1)/(n) (c) (2^(n)-1)/(n) (d) (2^(n+1)-1)/(n+1)

The value of 1+1.1!+2.2!+3.3!+.........+n.n! is (A) (n+1)!+1(B)(n-1)!+i(C)(n+1)!-1(D)(n+1)!

The sum of the series: (1)/(log_(2)4)+(1)/(log_(4)4)+(1)/(log_(8)4)+...+(1)/(log_(2n)4) is (n(n+1))/(2) (b) (n(n+1)(2n+1))/(12) (c) (n(n+1))/(4) (d) none of these

The coefficient of 1/x in the expansion of (1+x)^(n)(1+1/x)^(n) is (n!)/((n-1)!(n+1)!) b.((2n)!)/((n-1)!(n+1)!) c.((2n-1)!(2n+1)!)/((2n-1)!(2n+1)!) d.none of these

Find the sum of series upto n terms ((2n+1)/(2n-1))+3((2n+1)/(2n-1))^(2)+5((2n+1)/(2n-1))^(3)+