Respuesta :

Simplest way to solve this problem: substitute the value of i with 1,2,3 and then add all terms.

4*(1/2)¹⁻¹ + 4*(1/2)²⁻¹ + 4*(1/2)³⁻¹ = 4*1 +4*1/2 + 4*1/4= 4+2+1=7

Answer is 7.