Question

Suku ke-4 suatu barisan geometri adalah 375 jika U1 = 3 maka besar U6 = ?
mohon jawabannya ya kak

Answer 1

U1 = a = 3
U4 = 375 = a x r^(n-1)
375 = 3 x r^3
125 = r^3
r = 5
U6 = a x r^(n-1)
U6 = 3 x 5^5
= 3 x 3125
= 9375

Answer 2

Geometri :
Un=ar^n-1

U4 = 375
U1 = a = 3
U6 =?

cari rasionya dulu,
U4 = 3 r^n-1
375 = 3 r^4-1
375 = 3 r^3
125 = r^3
r = 5

terus kita cari deh U6nya pake rumus Un=ar^n-1
Un=ar^n-1
U6 = 3 × 5^6-1
= 3 × 5^5
= 3 × 3125
= 9375