Bonjour,
u = 5000
S = 5000
n = 5
i = 2:
u = 9 * 5000 / 5 = 9000
S = 5000 + 9000 = 14000
i = 3:
u = 9 * 9000 / 5 = 16200
S = 14000 + 16200 = 30200
i = 4:
u = 9 * 16200 / 5 = 29160
S = 30200 + 29160 = 59360
i = 5:
u = 9 * 29160 / 5 = 52488
S = 59360 + 52488 = 111848
Bonne journée.