[1+3+7+15..." n terms "=],[[" (A) "2^(n+1)-n-2," (B) "n^(2)+n-2],[" (C) "2^(n)+n^(2)-2," (D) "n^(2)+2]]

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

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

1.3+3.5+5.7+.....n terms =

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

3 + 5 + 7 + .... to n terms is

1 . 3+3 . 5+5 . 7+.. . . to n terms =

3+5+7+ …………. To n terms is

1/2+3/4+7/8+15/16+..... t o 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

[" If the ratio of the sum of "n" terms of two "],[" A.P.s is "(3n+8):(7n+15)" ,then the ratio "],[" of the "12],[" th term is "]