Pertanyaan
Diketahui barisan geometri dengan suku ke 3 adalah 3 dan suku ke 5 adalah 27 tentukan suku ke 7
Ditanyakan oleh: USER6287
95 Dilihat
95 Jawaban
Jawaban (95)
Un = a.r^(n-1)
U3 = 3
a.r^(3-1) = 3
a.r² = 3
a = 3/r²
U5 = 27
a.r^(5-1) = 27
a.r^4 = 27
a = 27/r^4
3/r² = 27/r^4
3r^4 = 27r²
r² = 9
r = 3
a = 3/r²
= 3/3²
= 1/3
U7 = a.r^(7 - 1)
= 1/3 × 3^6
= 1/3 × 729
= 243
U3 = 3
a.r^(3-1) = 3
a.r² = 3
a = 3/r²
U5 = 27
a.r^(5-1) = 27
a.r^4 = 27
a = 27/r^4
3/r² = 27/r^4
3r^4 = 27r²
r² = 9
r = 3
a = 3/r²
= 3/3²
= 1/3
U7 = a.r^(7 - 1)
= 1/3 × 3^6
= 1/3 × 729
= 243