Find the sum of nnn terms of 1+x+x2+…1 + x + x^2 + \dots1+x+x2+….
(xn−1)/(x−1)(x^n-1)/(x-1)(xn−1)/(x−1)
1/(1−x)1/(1-x)1/(1−x)
(1−xn)/(1−x)(1-x^n)/(1-x)(1−xn)/(1−x)
Both a and c