Hitunglah jumlah deret geometri 27 - 9 + 3 - .... Sampai 10 suku
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Penjelasan dengan langkah-langkah:
suku ganjil = 27, 3, ⅓, ...
suku genap = -9, -1, -1/9
S5.ganjil = 27 x (1 - ⅓^5)/(1 - ⅓)
= 27 x 3/2 x (243-1)/243
= 27/243 x 242
= 242/9
S5genap = -9 x (1 - 1/9^5)/(1 - 1/9)
= -9 x 9/8 x (59.048/59.049)
= -81/59.049 x 59.048/8
= -1/729 x 7.381
= -7.381/729
S10 = 242/9 - 7.381/729
S10 = 19.602/729 - 7.381/729
S10 = 12.221/729
[answer.2.content]
