U5= a + 4b =27
U3= a + 2b =17
___________ -
2b. =10
b =5
U3 =a +2b =17
a + 10=17
a. =17-10
=7
U8= 7+ (8-1)5
=7+ (7)5
=7+35
=42
Sn. = (a +Un ) n/2
S8. =( 7+42) 8/2
=(49) 4
=196
Diketahui:
U3 = a + 2b = 17
U5 = a + 4b = 27
Ditanyakan:
S8 = ... ?
Penyelesaian:
beda barisan
4b - 2b = 27 - 17
2b = 10
b = 5
suku pertama
a + 4b = 27
a + 4(5) = 27
a + 20 = 27
a = 7
Sn = n/2 (2a + (n - 1) b
S8 = 8/2 (2.7 + (8 - 1) 5
S8 = 4 (14 + 35)
S8 = 4 (49)
S8 = 196
==================
Kelas: 9
Mapel: Matematika
Bab: Barisan dan Deret Bilangan
Kode: 9.2.2
Kata Kunci: Deret aritmatika
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Verified answer
U5= a + 4b =27
U3= a + 2b =17
___________ -
2b. =10
b =5
U3 =a +2b =17
a + 10=17
a. =17-10
=7
U8= 7+ (8-1)5
=7+ (7)5
=7+35
=42
Sn. = (a +Un ) n/2
S8. =( 7+42) 8/2
=(49) 4
=196
Diketahui:
U3 = a + 2b = 17
U5 = a + 4b = 27
Ditanyakan:
S8 = ... ?
Penyelesaian:
beda barisan
4b - 2b = 27 - 17
2b = 10
b = 5
suku pertama
a + 4b = 27
a + 4(5) = 27
a + 20 = 27
a = 7
Sn = n/2 (2a + (n - 1) b
S8 = 8/2 (2.7 + (8 - 1) 5
S8 = 4 (14 + 35)
S8 = 4 (49)
S8 = 196
==================
Detil Jawaban
Kelas: 9
Mapel: Matematika
Bab: Barisan dan Deret Bilangan
Kode: 9.2.2
Kata Kunci: Deret aritmatika