`1+3+7+15+31+...+ ` to n terms

Find the sum of the series 3 + 7 + 13 + 21 + 31 + … to n terms . Find the sun when n=20

If S_(n) = 1 + 3 + 7 + 13 + 21 + "….." upto n terms, then

The sum 1+3+7+15+31+... to 100 terms is 2^(100)-102b b.2^(99)-101 c.2^(101)-102 d.none of these

Sum of the series 1+3+7+15+....... upto n terms.

The sum of the series 1-3+5-7+9-11+ . . . . To n terms is

Find the sum of the series cot^(-1) 7+cot^(-1)13+cot^(-1)21+cot^(-1)31+... to n terms

If n odd, then (1+3+5+7+ ….. to n terms) is equal to

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)/(3.5)+(1)/(5.7)+(1)/(7.9)+…….. up to n terms is equal to