Finding a closed form for these summations?

Question

Find a closed form for these summations?

 

  n=100

a) ∑ 1/2

   i=1

    

     n=5
b)  ∑ 1/3
     i=1

Answer 1

(a).  add 1/2 to itself 100 times to get 100(1/2) = 50

 

(b).  add 1/3 to itself 5 times to get 5(1/3) = 5/3