Find `1+ 1/(1+2)+1/(1+2+3)+….. to n` terms.

(1-1/n) + (1 - 2/n) + (1 - 3/n)+ …… upto n terms = ?

1+(1+2)+(1+2+3)+(1+2+3+4)+ to n terms.

(i) 1+(1+2)+(1+2+3)+………. to n terms. (ii) 1^(2)+(1^(2)+2^(2))+(1^(2)+2^(2)+3^(2))+ ………………to n terms.

Find the sum of the GP : (i) sqrt(7)+sqrt(21)+3sqrt(7)+... to n terms (ii) 1-1/3+1/3^(2)-1/3^(3)+... to n terms (iii) 1-a+a^(2)-a^(3)+... to n terms (a ne 1) (iv) x^(3)+x^(5)+x^(7)+... to terms (v) x(x+y)+x^(2)(x^(2)+y^(2))+x^(3) (x^(3)+y^(3))+... to n terms

(1)/(1.2)+(1)/(2.3)+(1)/(3.4)+... to n terms

Find the sum of the following. (1-(1)/(n))+(1-(2)/(n))+(1-(3)/(n))+... up to n terms.

Find the 1+ 1//2+1/4+1/8+… to n terms

Find the sum of n-terms: [(1/1)+(1^3 +2^3)/2 +(1^3 +2^3 +3^3)/3+....to n -terms

Find the sum to n terms of the series S_(n)=cot^(-1)(2^(2)+(1)/(2))+cot^(-1)(2^(3)+(1)/(2^(2)))+cot^(-1)(2^(4)+(1)/(2^(3)))+..... upto n terms ?

Find the sum 1+(1)/(1+2)+(1)/(1+2+3)+......+(1)/(1+2+3+......+n)