help with expanded form

Question

how do I write this series in explanded form?

 

  ₅

 ∑ 1/2k

 _k=11

Answer 1

 

Here it is for k=1 (vice k=11) to k=5:

 

5
∑ (1/2)k = (1/2)(1) + (1/2)(2) + (1/2)(3) + (1/2)(4) + (1/2)(5)
k=1

 

= (1/2) + 1 + (3/2) + 2 + (5/2) = ?