If `alpha (!=1)` is a nth root of unity then `S = 1 + 3alpha+ 5alpha^2 + .......... `upto n terms is equal to

If alpha(!=1) is a nth root of unity then S=1+3 alpha+5 alpha^(2)+......... upto n terms is equal to

If alpha is the nth root of unity then 1+2alpha+3alpha^(2)+ ............to n terms is equal to

If alpha is the nth root of unity then prove that 1+2 alpha+ 3 alpha^2+…. upto n terms

If alpha is the complex fifth root of unity, then |1+alpha + alpha^(2)| =

If 1,alpha,alpha^(2),......alpha^(n-1) are n,n^(th) roots ofunity, then 1+2 alpha+3 alpha^(2)+4 alpha^(3)+......+n terms is equal to

If alpha is the nth root of unity then 1+2alpha+3alpha^2+…. to n terms equal to

If alpha is the nth root of unity, then 1+2alpha+3alpha^2+ ton terms equal to a. (-n)/((1-alpha)^2) b. (-n)/(1-alpha) c. (-2n)/(1-alpha)"" d. (-2n)/((1-alpha)^2)

If alpha is the nth root of unity, then 1+2alpha+3alpha^2+ ton terms equal to a. (-n)/((1-alpha)^2) b. (-n)/(1-alpha) c. (-2n)/(1-alpha)"" d. (-2n)/((1-alpha)^2)