Respuesta :

DeanR

This is a geometric series, 0th term 5, common factor 0.5, so

y = 5 (0.5)ˣ

Check: f(0)= 5,   f(1) = 5(.5)=2.5, f(2) = 5(.5)² = 1.25, f(3)=5(.5)³=0.625

Answer: y = 5 (0.5)ˣ