If `(n+1)! =90[(n-1)!],` fin d n

If (n+1)! =90 xx(n-1)!, find n .

If (n+3)!=56[(n+1)! fin n

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)!)/((2n-1)!(2n+1)!) 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)!)/((2n-1)!(2n+1)!) d. none of these

sum_(k=1)^ook(1-1/n)^(k-1)=>? a. n(n-1) b. n(n+1) c. n^2 d. (n+1)^2

sum_(k=1)^ook(1-1/n)^(k-1)= a. n(n-1) b. n(n+1) c. n^2 d. (n+1)^2

Let f(n)=1+1/2+1/3++1/ndot Then f(1)+f(2)+f(3)++f(n) is equal to (a) nf(n)-1 (b) (n+1)f(n)-n (c) (n+1)f(n)+n (d) nf(n)+n

Let f(n)=1+1/2+1/3++1/ndot Then f(1)+f(2)+f(3)++f(n) is equal to (a) nf(n)-1 (b) (n+1)f(n)-n (c) (n+1)f(n)+n (d) nf(n)+n